Biological Molecules Quiz Questions

1. Which polymer contains nitrogen?

Chitin

Cellulose

Starch

Glycogen

Chitin is the correct answer because it is a polymer that contains nitrogen. Chitin is a structural polysaccharide found in the exoskeletons of arthropods and the cell walls of fungi. It is composed of repeating units of N-acetylglucosamine, which contains nitrogen. Cellulose, starch, and glycogen are all polysaccharides but do not contain nitrogen.

Explanation

Chitin is the correct answer because it is a polymer that contains nitrogen. Chitin is a structural polysaccharide found in the exoskeletons of arthropods and the cell walls of fungi. It is composed of repeating units of N-acetylglucosamine, which contains nitrogen. Cellulose, starch, and glycogen are all polysaccharides but do not contain nitrogen.

2. Biggest difference between prokaryotic cells and eukaryotic cells

Membrane bound organelles

Plasma membrane

Selective permeability

Containing DNA

The biggest difference between prokaryotic cells and eukaryotic cells is the presence of membrane-bound organelles. Prokaryotic cells lack membrane-bound organelles, while eukaryotic cells have various membrane-bound organelles such as mitochondria, endoplasmic reticulum, and Golgi apparatus. These organelles perform specific functions within the cell, allowing for compartmentalization and specialization of cellular processes. This distinction in cellular organization is a fundamental characteristic that sets prokaryotic and eukaryotic cells apart.

Explanation

The biggest difference between prokaryotic cells and eukaryotic cells is the presence of membrane-bound organelles. Prokaryotic cells lack membrane-bound organelles, while eukaryotic cells have various membrane-bound organelles such as mitochondria, endoplasmic reticulum, and Golgi apparatus. These organelles perform specific functions within the cell, allowing for compartmentalization and specialization of cellular processes. This distinction in cellular organization is a fundamental characteristic that sets prokaryotic and eukaryotic cells apart.

3. Match the nitrogenous bases for DNA:

Adenine

Cytosine

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4. Match the following nitrogenous bases in RNA:

Uracil

Guanine

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5. After you drink acidic lemonade, your body stays at the same pH. This is an example of...

Maintaining homeostasis

Growth

Evolve in response to environment

Behavior

Maintain cellular organization

Immunization to weak acids

The fact that your body stays at the same pH after drinking acidic lemonade suggests that it is maintaining homeostasis. Homeostasis refers to the body's ability to regulate and maintain a stable internal environment despite external changes. In this case, your body is able to balance the pH levels and keep it within a normal range, even after consuming an acidic substance like lemonade. This is an example of the body's ability to maintain homeostasis.

Explanation

The fact that your body stays at the same pH after drinking acidic lemonade suggests that it is maintaining homeostasis. Homeostasis refers to the body's ability to regulate and maintain a stable internal environment despite external changes. In this case, your body is able to balance the pH levels and keep it within a normal range, even after consuming an acidic substance like lemonade. This is an example of the body's ability to maintain homeostasis.

6. Match the following RNA to it's function

transports amino acids

carries codes to ribosome to make protein

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7. What do you call elements with the same number of protons but different atomic masses?

Isotopes are elements that have the same number of protons but differ in their atomic masses. This is because isotopes have different numbers of neutrons in their nuclei. The variation in the number of neutrons results in different atomic masses for the same element. Isotopes can have slightly different physical and chemical properties due to the variation in atomic mass, but they still belong to the same element because they have the same number of protons.

Explanation

Isotopes are elements that have the same number of protons but differ in their atomic masses. This is because isotopes have different numbers of neutrons in their nuclei. The variation in the number of neutrons results in different atomic masses for the same element. Isotopes can have slightly different physical and chemical properties due to the variation in atomic mass, but they still belong to the same element because they have the same number of protons.

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8. Of the following is true of both starch and cellulose?

They are both polymers of glucose.

They are cis-trans isomers of each other.

They can both be digested by humans.

They are both used for energy storage in plants.

They are both structural components of the plant cell wall.

Both starch and cellulose are polymers of glucose. Starch is a polysaccharide composed of glucose units and serves as a storage form of energy in plants. It is easily digested by humans. Cellulose, on the other hand, is also a polysaccharide made up of glucose units but has a different arrangement, making it indigestible for humans. Cellulose functions as a structural component of the plant cell wall, providing rigidity and support.

Explanation

Both starch and cellulose are polymers of glucose. Starch is a polysaccharide composed of glucose units and serves as a storage form of energy in plants. It is easily digested by humans. Cellulose, on the other hand, is also a polysaccharide made up of glucose units but has a different arrangement, making it indigestible for humans. Cellulose functions as a structural component of the plant cell wall, providing rigidity and support.

9. The control group is the group without the changed variable and it forms baseline for comparisons.

True

False

Experimental: group with the changed variable
Control: group without the changed variable, forms baseline for comparisons.

Explanation

Experimental: group with the changed variable
Control: group without the changed variable, forms baseline for comparisons.

10. What makes fat hydrophobic?

The fatty acid tail is nonpolar

The fatty acid tail is polar

Because of the nitrogen present

Because of the oxygen present

The correct answer is that the fatty acid tail is nonpolar. This means that it does not have a charge and does not interact well with water molecules, which are polar. Hydrophobic substances, like fats, repel water because their nonpolar nature prevents them from forming favorable interactions with polar molecules.

Explanation

The correct answer is that the fatty acid tail is nonpolar. This means that it does not have a charge and does not interact well with water molecules, which are polar. Hydrophobic substances, like fats, repel water because their nonpolar nature prevents them from forming favorable interactions with polar molecules.

11. Match the following types of reactions:

build up (store energy)

break down (provide energy)

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12. Which is a type of steroid?

Cholesterol

Sugar

Galactose

Adenine

Thymine

Glycerine

Cholesterol is a type of steroid. Steroids are a class of organic compounds that have a characteristic structure of four fused rings. Cholesterol is a sterol, which is a subgroup of steroids that have a hydroxyl group at the 3-position. It is an essential component of cell membranes and is also involved in the production of hormones, vitamin D, and bile acids. Cholesterol is mainly synthesized in the liver and is also obtained from dietary sources. High levels of cholesterol in the blood can increase the risk of heart disease.

Explanation

Cholesterol is a type of steroid. Steroids are a class of organic compounds that have a characteristic structure of four fused rings. Cholesterol is a sterol, which is a subgroup of steroids that have a hydroxyl group at the 3-position. It is an essential component of cell membranes and is also involved in the production of hormones, vitamin D, and bile acids. Cholesterol is mainly synthesized in the liver and is also obtained from dietary sources. High levels of cholesterol in the blood can increase the risk of heart disease.

13. One of the primary functions of RNA molecules is to

Function in the synthesis of proteins.

Transmit genetic information to offspring.

Make a copy of itself, thus ensuring genetic continuity.

Act as a pattern or blueprint to form DNA.

Form the genes of higher organisms.

RNA molecules play a crucial role in protein synthesis. They act as messengers, carrying the genetic information from DNA to the ribosomes, where proteins are synthesized. RNA molecules are transcribed from DNA and then translated into proteins. This process is known as gene expression. Therefore, one of the primary functions of RNA molecules is to function in the synthesis of proteins.

Explanation

RNA molecules play a crucial role in protein synthesis. They act as messengers, carrying the genetic information from DNA to the ribosomes, where proteins are synthesized. RNA molecules are transcribed from DNA and then translated into proteins. This process is known as gene expression. Therefore, one of the primary functions of RNA molecules is to function in the synthesis of proteins.

14. Why are human sex hormones considered to be lipids?

Because they are not soluble in water

Because they are soluble in water

Because they contain fats

Because they contain proteins

Human sex hormones, such as estrogen and testosterone, are considered to be lipids because they are not soluble in water. Lipids are a group of molecules that are hydrophobic, meaning they repel water. Human sex hormones are made up of carbon, hydrogen, and oxygen atoms, which gives them a nonpolar structure. This nonpolar nature prevents them from dissolving in water but allows them to dissolve in other lipids and nonpolar solvents. Therefore, the fact that human sex hormones are not soluble in water classifies them as lipids.

Explanation

Human sex hormones, such as estrogen and testosterone, are considered to be lipids because they are not soluble in water. Lipids are a group of molecules that are hydrophobic, meaning they repel water. Human sex hormones are made up of carbon, hydrogen, and oxygen atoms, which gives them a nonpolar structure. This nonpolar nature prevents them from dissolving in water but allows them to dissolve in other lipids and nonpolar solvents. Therefore, the fact that human sex hormones are not soluble in water classifies them as lipids.

15. A substance with specific properties that can not be broken down or converted to another substance is a(n):

Element

Compound

Molecule

Protein

An element is a substance with specific properties that cannot be broken down or converted into another substance. Elements are made up of only one type of atom and cannot be further simplified. Unlike compounds, which are made up of two or more different elements, elements exist on their own. Molecules, on the other hand, can be made up of either one element or multiple elements. Proteins, while they are made up of atoms, are not considered elements as they can be broken down into smaller components called amino acids.

Explanation

An element is a substance with specific properties that cannot be broken down or converted into another substance. Elements are made up of only one type of atom and cannot be further simplified. Unlike compounds, which are made up of two or more different elements, elements exist on their own. Molecules, on the other hand, can be made up of either one element or multiple elements. Proteins, while they are made up of atoms, are not considered elements as they can be broken down into smaller components called amino acids.

16. If an atom has a charge of +1 that means...

It has 1 more neutron than protons and electron

It has 1 more proton than electrons

It has 1 more electron than protons

It has same number of protons and electrons

If an atom has a charge of +1, it means that it has lost one electron. Since electrons have a negative charge, losing one electron would result in a net positive charge for the atom. Therefore, the atom would have one more proton than electrons, as protons have a positive charge.

Explanation

If an atom has a charge of +1, it means that it has lost one electron. Since electrons have a negative charge, losing one electron would result in a net positive charge for the atom. Therefore, the atom would have one more proton than electrons, as protons have a positive charge.

17. Most biological bonds in the body are..

Covalent

Ionic

Hydrogen

Peptide

Most biological bonds in the body are covalent. Covalent bonds involve the sharing of electrons between atoms, resulting in a strong bond. In biological molecules such as proteins, nucleic acids, and carbohydrates, covalent bonds are essential for maintaining the structure and function of these molecules. These bonds are formed through the sharing of electrons in the outermost energy levels of atoms, creating stable and durable connections. Covalent bonds are crucial for the stability and integrity of biological systems, allowing for the formation of complex structures and the transmission of genetic information.

Explanation

Most biological bonds in the body are covalent. Covalent bonds involve the sharing of electrons between atoms, resulting in a strong bond. In biological molecules such as proteins, nucleic acids, and carbohydrates, covalent bonds are essential for maintaining the structure and function of these molecules. These bonds are formed through the sharing of electrons in the outermost energy levels of atoms, creating stable and durable connections. Covalent bonds are crucial for the stability and integrity of biological systems, allowing for the formation of complex structures and the transmission of genetic information.

18. The function of the endomembrane system?

Regulates protein traffic and performs metabolic functions in the cell.

Powerhouse of the cell

Stores DNA

Stores water

The endomembrane system in a cell is responsible for regulating protein traffic and performing metabolic functions. It consists of various organelles such as the endoplasmic reticulum, Golgi apparatus, lysosomes, and vesicles. These organelles work together to synthesize, modify, package, and transport proteins within the cell. They also play a role in lipid metabolism, detoxification, and calcium storage. Therefore, the correct answer is that the endomembrane system regulates protein traffic and performs metabolic functions in the cell.

Explanation

The endomembrane system in a cell is responsible for regulating protein traffic and performing metabolic functions. It consists of various organelles such as the endoplasmic reticulum, Golgi apparatus, lysosomes, and vesicles. These organelles work together to synthesize, modify, package, and transport proteins within the cell. They also play a role in lipid metabolism, detoxification, and calcium storage. Therefore, the correct answer is that the endomembrane system regulates protein traffic and performs metabolic functions in the cell.

19.

Which bonds are created during the formation of the primary structure of a protein?

During the formation of the primary structure of a protein, peptide bonds are created. Peptide bonds are formed by a condensation reaction between the carboxyl group of one amino acid and the amino group of another amino acid. These bonds link the amino acids together in a linear chain, forming the backbone of the protein. The resulting chain of amino acids is called a peptide. Therefore, the correct answer is peptide bonds and peptide.

Explanation

During the formation of the primary structure of a protein, peptide bonds are created. Peptide bonds are formed by a condensation reaction between the carboxyl group of one amino acid and the amino group of another amino acid. These bonds link the amino acids together in a linear chain, forming the backbone of the protein. The resulting chain of amino acids is called a peptide. Therefore, the correct answer is peptide bonds and peptide.

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20. What does H-O-H represent?

H-O-H represents the chemical formula of water, which consists of two hydrogen atoms bonded to one oxygen atom. This arrangement forms a molecule of water, commonly known as water.

Explanation

H-O-H represents the chemical formula of water, which consists of two hydrogen atoms bonded to one oxygen atom. This arrangement forms a molecule of water, commonly known as water.

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21. Which of the following is true of carbon?

It can form polar and nonpolar bonds.

It only forms polar molecules.

It is highly electronegative.

It can form a maximum of three covalent bonds with other elements.

Carbon is a versatile element that can form both polar and nonpolar bonds. This is because carbon has four valence electrons, allowing it to form up to four covalent bonds with other elements. Depending on the atoms it bonds with and the arrangement of these bonds, carbon can form both polar and nonpolar molecules. The ability of carbon to form a variety of bonds is the basis for the vast diversity of organic compounds found in nature.

Explanation

Carbon is a versatile element that can form both polar and nonpolar bonds. This is because carbon has four valence electrons, allowing it to form up to four covalent bonds with other elements. Depending on the atoms it bonds with and the arrangement of these bonds, carbon can form both polar and nonpolar molecules. The ability of carbon to form a variety of bonds is the basis for the vast diversity of organic compounds found in nature.

22. Atoms with unequal # of protons and electrons

Atoms with unequal numbers of protons and electrons are called ions. When an atom gains or loses electrons, it becomes electrically charged. If an atom gains electrons, it becomes negatively charged and is called an anion. On the other hand, if an atom loses electrons, it becomes positively charged and is called a cation. These charged atoms are referred to as ions.

Explanation

Atoms with unequal numbers of protons and electrons are called ions. When an atom gains or loses electrons, it becomes electrically charged. If an atom gains electrons, it becomes negatively charged and is called an anion. On the other hand, if an atom loses electrons, it becomes positively charged and is called a cation. These charged atoms are referred to as ions.

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23. For an atom to achieve maximum stability and become chemically inert, what must occur?

Electron pairs are shared.

Its outermost energy shell must be filled with electrons.

The number of electrons must equal the number of protons.

Ionization occurs.

In order for an atom to achieve maximum stability and become chemically inert, its outermost energy shell must be filled with electrons. This is because the outermost energy shell, also known as the valence shell, determines the atom's reactivity. When the valence shell is completely filled with electrons, the atom is stable and less likely to react with other atoms. This stability is achieved by either gaining, losing, or sharing electrons with other atoms to fill the valence shell.

Explanation

In order for an atom to achieve maximum stability and become chemically inert, its outermost energy shell must be filled with electrons. This is because the outermost energy shell, also known as the valence shell, determines the atom's reactivity. When the valence shell is completely filled with electrons, the atom is stable and less likely to react with other atoms. This stability is achieved by either gaining, losing, or sharing electrons with other atoms to fill the valence shell.

24.

The tertiary structure of a protein is the

Order in which amino acids are joined in a polypeptide chain.

Overall protein structure resulting from the aggregation of two or more polypeptide subunits.

Unique three-dimensional shape of the fully folded polypeptide.

Bonding together of several polypeptide chains by weak bonds.

The tertiary structure of a protein refers to the unique three-dimensional shape that the fully folded polypeptide adopts. This structure is determined by the interactions between the amino acid side chains and the surrounding environment, including hydrogen bonds, disulfide bonds, hydrophobic interactions, and electrostatic interactions. The specific arrangement of these interactions gives the protein its characteristic shape, which is essential for its proper function.

Explanation

The tertiary structure of a protein refers to the unique three-dimensional shape that the fully folded polypeptide adopts. This structure is determined by the interactions between the amino acid side chains and the surrounding environment, including hydrogen bonds, disulfide bonds, hydrophobic interactions, and electrostatic interactions. The specific arrangement of these interactions gives the protein its characteristic shape, which is essential for its proper function.

25. What is this?

Saturated fatty acid

Unsaturated fatty acid

Protein

Amino acid

Carbohydrate

A saturated fatty acid is a type of fat molecule that contains only single bonds between carbon atoms and is saturated with hydrogen atoms. This means that all carbon atoms in the fatty acid chain are bonded to the maximum number of hydrogen atoms possible. Saturated fatty acids are typically solid at room temperature and are commonly found in animal products such as meat and dairy. They are known to contribute to an increased risk of heart disease when consumed in excess.

Explanation

A saturated fatty acid is a type of fat molecule that contains only single bonds between carbon atoms and is saturated with hydrogen atoms. This means that all carbon atoms in the fatty acid chain are bonded to the maximum number of hydrogen atoms possible. Saturated fatty acids are typically solid at room temperature and are commonly found in animal products such as meat and dairy. They are known to contribute to an increased risk of heart disease when consumed in excess.

26. Function of organelles that change energy to one form to another:

Contains enzymes that transfer hydrogen atoms from certain molecules to oxygen, producing hydrogen peroxide

cellular respiration

photosynthesis

Peroxisome: Contains enzymes that transfer hydrogen atoms from certain molecules to oxygen, producing hydrogen peroxide (H2O2), as a by-product; H2O2 is converted to water by another enzyme

Explanation

Peroxisome: Contains enzymes that transfer hydrogen atoms from certain molecules to oxygen, producing hydrogen peroxide (H2O2), as a by-product; H2O2 is converted to water by another enzyme

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27. Match the following:

"water-fearing"

"water-loving" / affinity for water

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28. Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified?

Starch

Disaccharide

Pentose

Polysaccharide

Monosaccharide

Lactose is classified as a disaccharide because it is composed of two sugar molecules, glucose and galactose, joined together by a glycosidic linkage. A disaccharide is a type of carbohydrate that consists of two monosaccharide units. Starch, pentose, and polysaccharide are not correct classifications for lactose because they refer to different types of carbohydrates. Monosaccharide is also not the correct classification because lactose is made up of two sugar molecules, not one.

Explanation

Lactose is classified as a disaccharide because it is composed of two sugar molecules, glucose and galactose, joined together by a glycosidic linkage. A disaccharide is a type of carbohydrate that consists of two monosaccharide units. Starch, pentose, and polysaccharide are not correct classifications for lactose because they refer to different types of carbohydrates. Monosaccharide is also not the correct classification because lactose is made up of two sugar molecules, not one.

29. Using its antennae, the male moth finds female moths by following a trail of airborne chemicals, called pheromones, upwind from the female producing them. This is an example of...

Reproduction

Response to stimuli

Grow

Acquire nutrients

Homeostasis

The given scenario describes how the male moth uses its antennae to detect and follow the trail of pheromones released by the female moth. This behavior is a direct response to the stimuli of the airborne chemicals. Therefore, the correct answer is "response to stimuli."

Explanation

The given scenario describes how the male moth uses its antennae to detect and follow the trail of pheromones released by the female moth. This behavior is a direct response to the stimuli of the airborne chemicals. Therefore, the correct answer is "response to stimuli."

30.

If ¹⁴C-labeled uracil is added to the growth medium of cells, what macromolecules will be labeled?

DNA

Both DNA and RNA

RNA

Proteins

Phospholipids

When 14C-labeled uracil is added to the growth medium of cells, the macromolecules that will be labeled are RNA. This is because uracil is a component of RNA, specifically in the form of ribonucleotides. DNA, on the other hand, does not contain uracil but instead contains thymine. Therefore, only RNA molecules will incorporate the labeled uracil and become labeled themselves.

Explanation

When 14C-labeled uracil is added to the growth medium of cells, the macromolecules that will be labeled are RNA. This is because uracil is a component of RNA, specifically in the form of ribonucleotides. DNA, on the other hand, does not contain uracil but instead contains thymine. Therefore, only RNA molecules will incorporate the labeled uracil and become labeled themselves.

31. Fatty acids are formed by dehydration reactions.

True

False

Fatty acids are not formed by dehydration reactions. Dehydration reactions involve the removal of water molecules to form larger molecules. Fatty acids, on the other hand, are typically formed through the process of hydrolysis, which involves the addition of water molecules to break down larger molecules into smaller ones. Therefore, the statement that fatty acids are formed by dehydration reactions is false.

Explanation

Fatty acids are not formed by dehydration reactions. Dehydration reactions involve the removal of water molecules to form larger molecules. Fatty acids, on the other hand, are typically formed through the process of hydrolysis, which involves the addition of water molecules to break down larger molecules into smaller ones. Therefore, the statement that fatty acids are formed by dehydration reactions is false.

32.

Which of the following statements is true for the class of biological molecules known as lipids?

They are insoluble in water.

They are soluble in water.

They contain nitrogen.

They are made of amino acids.

They are made from glycerol, fatty acids, and phosphate

They contain less energy than proteins and carbohydrates.

They are made by dehydration reactions

Lipids are a class of biological molecules that are insoluble in water. This is because they are hydrophobic, meaning they repel water molecules. Lipids have a nonpolar structure, which prevents them from forming hydrogen bonds with water molecules. Instead, lipids tend to aggregate together, forming structures such as cell membranes or fat droplets. Lipids play important roles in energy storage, insulation, and cell signaling.

Explanation

Lipids are a class of biological molecules that are insoluble in water. This is because they are hydrophobic, meaning they repel water molecules. Lipids have a nonpolar structure, which prevents them from forming hydrogen bonds with water molecules. Instead, lipids tend to aggregate together, forming structures such as cell membranes or fat droplets. Lipids play important roles in energy storage, insulation, and cell signaling.

33. Which of the following typically has more potential energy than kinetic energy?

Heat

Chemical bonds

Motion

All lack potential energy

Chemical bonds typically have more potential energy than kinetic energy. Potential energy refers to the stored energy that an object possesses due to its position or state. Chemical bonds store energy in the form of potential energy, which is released as kinetic energy when the bonds are broken and a chemical reaction occurs. This is why chemical reactions often involve the release or absorption of energy. Heat and motion, on the other hand, are forms of kinetic energy, as they involve the movement or transfer of energy.

Explanation

Chemical bonds typically have more potential energy than kinetic energy. Potential energy refers to the stored energy that an object possesses due to its position or state. Chemical bonds store energy in the form of potential energy, which is released as kinetic energy when the bonds are broken and a chemical reaction occurs. This is why chemical reactions often involve the release or absorption of energy. Heat and motion, on the other hand, are forms of kinetic energy, as they involve the movement or transfer of energy.

34. Simple carbohydrates are the main source of immediate _____.

Simple carbohydrates (sugar, glucose, fructose etc) are the main source of immediate energy. That is, they are metabolized easily and quickly. All our cells can use glucose for energy, so once it is metabolized and reaches the blood stream it can travel to other cells and tissues.

Explanation

Simple carbohydrates (sugar, glucose, fructose etc) are the main source of immediate energy. That is, they are metabolized easily and quickly. All our cells can use glucose for energy, so once it is metabolized and reaches the blood stream it can travel to other cells and tissues.

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35. The smallest units that still retain the characteristics of an element are called

Atoms are the smallest units that retain the properties and characteristics of an element. They are the building blocks of matter and cannot be broken down into smaller particles without losing their elemental properties. Each atom consists of a nucleus containing protons and neutrons, surrounded by electrons in energy levels. Atoms combine to form molecules and compounds, and their unique arrangements and interactions determine the properties and behavior of different substances. Therefore, atoms are the correct answer for the question.

Explanation

Atoms are the smallest units that retain the properties and characteristics of an element. They are the building blocks of matter and cannot be broken down into smaller particles without losing their elemental properties. Each atom consists of a nucleus containing protons and neutrons, surrounded by electrons in energy levels. Atoms combine to form molecules and compounds, and their unique arrangements and interactions determine the properties and behavior of different substances. Therefore, atoms are the correct answer for the question.

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36.

Which level of protein structure do the α helix and the β pleated sheet represent?

Secondary

Primary

Quarternary

Tertiary

All of the above

The α helix and β pleated sheet represent the secondary level of protein structure. Secondary structure refers to the local folding patterns of the polypeptide chain, specifically the regular repeating structures formed by hydrogen bonding between the amino acid residues. The α helix is a coiled structure, while the β pleated sheet consists of strands of the polypeptide chain lying side by side, forming a sheet-like structure. The primary structure refers to the linear sequence of amino acids, while the tertiary and quaternary structures involve the overall 3D folding and interactions between multiple polypeptide chains, respectively.

Explanation

The α helix and β pleated sheet represent the secondary level of protein structure. Secondary structure refers to the local folding patterns of the polypeptide chain, specifically the regular repeating structures formed by hydrogen bonding between the amino acid residues. The α helix is a coiled structure, while the β pleated sheet consists of strands of the polypeptide chain lying side by side, forming a sheet-like structure. The primary structure refers to the linear sequence of amino acids, while the tertiary and quaternary structures involve the overall 3D folding and interactions between multiple polypeptide chains, respectively.

37.

Which of the following is not a monomer/polymer pairing?

Triglyceride/phospholipid bilayer

Deoxyribonucleotide/DNA

Amino acid/protein

Ribonucleotide/RNA

Monosaccharide/polysaccharide

The correct answer is triglyceride/phospholipid bilayer. Triglyceride is a type of lipid composed of three fatty acids and glycerol, while a phospholipid bilayer is a type of lipid that forms the cell membrane. Although both triglycerides and phospholipids are lipids, they have different structures and functions. Triglycerides are used for energy storage, while phospholipids are essential for cell structure and function. Therefore, triglyceride/phospholipid bilayer is not a monomer/polymer pairing.

Explanation

The correct answer is triglyceride/phospholipid bilayer. Triglyceride is a type of lipid composed of three fatty acids and glycerol, while a phospholipid bilayer is a type of lipid that forms the cell membrane. Although both triglycerides and phospholipids are lipids, they have different structures and functions. Triglycerides are used for energy storage, while phospholipids are essential for cell structure and function. Therefore, triglyceride/phospholipid bilayer is not a monomer/polymer pairing.

38. All of the following are TRUE about living organisms EXCEPT...

Reproduce themselves

Grow into multicellular organisms

Have an active metabolism

Are made of cells

Respond to stimuli

Living organisms can grow into multicellular organisms, so this statement is not true. All living organisms have the ability to reproduce, have an active metabolism, are made of cells, and respond to stimuli. However, not all living organisms grow into multicellular organisms. Some organisms, such as bacteria and single-celled protists, remain as single cells throughout their life cycle. Therefore, the statement "grow into multicellular organisms" is not true for all living organisms.

Explanation

Living organisms can grow into multicellular organisms, so this statement is not true. All living organisms have the ability to reproduce, have an active metabolism, are made of cells, and respond to stimuli. However, not all living organisms grow into multicellular organisms. Some organisms, such as bacteria and single-celled protists, remain as single cells throughout their life cycle. Therefore, the statement "grow into multicellular organisms" is not true for all living organisms.

39. Categorize these carbohydrates (sugars):

glucose

sucrose

starch

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40. The element present in all organic molecules is

Carbon is the element that is present in all organic molecules. This is because carbon has the unique ability to form covalent bonds with other carbon atoms and a variety of other elements, allowing for the formation of complex and diverse organic compounds. Organic molecules are defined as compounds that contain carbon atoms bonded to hydrogen atoms, along with other elements such as oxygen, nitrogen, and sulfur. Therefore, carbon is the fundamental element in organic chemistry and is essential for the existence of life as we know it.

Explanation

Carbon is the element that is present in all organic molecules. This is because carbon has the unique ability to form covalent bonds with other carbon atoms and a variety of other elements, allowing for the formation of complex and diverse organic compounds. Organic molecules are defined as compounds that contain carbon atoms bonded to hydrogen atoms, along with other elements such as oxygen, nitrogen, and sulfur. Therefore, carbon is the fundamental element in organic chemistry and is essential for the existence of life as we know it.

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41. The structural formula for a certain molecule includes a group symbolized -O. The dash next to the oxygen atom means that a single bond exists to another atom, such as a carbon. Based on the valence of oxygen and the number of bonds it normally forms, what is the charge on the oxygen atom in this case?

-2

-1

+1

+2

The dash next to the oxygen atom indicates that it is bonded to another atom, such as carbon, through a single bond. Oxygen typically forms two bonds, so in this case, it has one bond remaining. Since oxygen has six valence electrons, and it needs eight to have a full octet, it will gain one electron to achieve stability. Gaining an electron results in a negative charge, so the charge on the oxygen atom in this case is -1.

Explanation

The dash next to the oxygen atom indicates that it is bonded to another atom, such as carbon, through a single bond. Oxygen typically forms two bonds, so in this case, it has one bond remaining. Since oxygen has six valence electrons, and it needs eight to have a full octet, it will gain one electron to achieve stability. Gaining an electron results in a negative charge, so the charge on the oxygen atom in this case is -1.

42. DNA Strand: Single Strand DNA sequence = AGCTAACTGGDNA complementary strand = _____mRNA strand = _____

The given DNA strand is AGCTAACTGG. To find the complementary strand, we need to replace each nucleotide with its complementary base. A pairs with T, G pairs with C, C pairs with G, and T pairs with A. Therefore, the complementary strand is TCGATTGACC. To find the mRNA strand, we need to replace each T with U. So, the mRNA strand is UCGAUUGACC.

Explanation

The given DNA strand is AGCTAACTGG. To find the complementary strand, we need to replace each nucleotide with its complementary base. A pairs with T, G pairs with C, C pairs with G, and T pairs with A. Therefore, the complementary strand is TCGATTGACC. To find the mRNA strand, we need to replace each T with U. So, the mRNA strand is UCGAUUGACC.

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43. How many electrons are involved in a single covalent bond?

In a single covalent bond, two electrons are involved. Covalent bonds occur when atoms share electrons to achieve a stable electron configuration. Each atom contributes one electron to the bond, resulting in a shared pair of electrons. This shared pair of electrons creates a strong bond between the atoms, allowing them to form molecules. Therefore, the correct answer is 2 or two.

Explanation

In a single covalent bond, two electrons are involved. Covalent bonds occur when atoms share electrons to achieve a stable electron configuration. Each atom contributes one electron to the bond, resulting in a shared pair of electrons. This shared pair of electrons creates a strong bond between the atoms, allowing them to form molecules. Therefore, the correct answer is 2 or two.

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44. What maintains the secondary structure of a protein?

Hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond

Covalent bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond

Ionic bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond

Peptide bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond

Hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond maintain the secondary structure of a protein. These hydrogen bonds form between the peptide backbone atoms, specifically between the nitrogen atom of one amino acid and the oxygen atom of another amino acid. These bonds stabilize the folding of the protein into secondary structures such as alpha helices and beta sheets. Covalent bonds and ionic bonds do not play a significant role in maintaining the secondary structure, while peptide bonds are responsible for connecting amino acids in the primary structure of a protein.

Explanation

Hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond maintain the secondary structure of a protein. These hydrogen bonds form between the peptide backbone atoms, specifically between the nitrogen atom of one amino acid and the oxygen atom of another amino acid. These bonds stabilize the folding of the protein into secondary structures such as alpha helices and beta sheets. Covalent bonds and ionic bonds do not play a significant role in maintaining the secondary structure, while peptide bonds are responsible for connecting amino acids in the primary structure of a protein.

45. Which of these classes of biological molecules consist of both small molecules and macromolecular polymers?

Carbohydrates

Lipids

Proteins

Nucleic acids

Lipids, carbohydrates, proteins, and nucleic acids all consist of only macromolecular polymers

Carbohydrates consist of both small molecules (such as monosaccharides) and macromolecular polymers (such as polysaccharides). Lipids, proteins, and nucleic acids are primarily macromolecular polymers but do not consist of small molecules.

Explanation

Carbohydrates consist of both small molecules (such as monosaccharides) and macromolecular polymers (such as polysaccharides). Lipids, proteins, and nucleic acids are primarily macromolecular polymers but do not consist of small molecules.

46. Humans can digest starch but not cellulose because

The monomer of starch is glucose, while the monomer of cellulose is galactose.

Humans have enzymes that can hydrolyze the β glycosidic linkages of starch but not the α glycosidic linkages of cellulose.

Humans have enzymes that can hydrolyze the α glycosidic linkages of starch but not the β glycosidic linkages of cellulose.

Humans harbor starch-digesting bacteria in the digestive tract.

The monomer of starch is glucose, while the monomer of cellulose is glucose with a nitrogen-containing group.

The correct answer is that humans have enzymes that can hydrolyze the α glycosidic linkages of starch but not the β glycosidic linkages of cellulose. This is because the enzymes in our digestive system, such as amylase, are specifically designed to break down the α glycosidic linkages found in starch. However, we lack the enzymes necessary to break down the β glycosidic linkages in cellulose. Therefore, while we can digest starch and obtain energy from it, we cannot digest cellulose and it passes through our digestive system as dietary fiber.

Explanation

The correct answer is that humans have enzymes that can hydrolyze the α glycosidic linkages of starch but not the β glycosidic linkages of cellulose. This is because the enzymes in our digestive system, such as amylase, are specifically designed to break down the α glycosidic linkages found in starch. However, we lack the enzymes necessary to break down the β glycosidic linkages in cellulose. Therefore, while we can digest starch and obtain energy from it, we cannot digest cellulose and it passes through our digestive system as dietary fiber.

47. The type of bonds present in a molecule determine its properties. Which type of bond is associated with molecules that are soluble in water (i.e., molecules that do not precipitate)

Strong ionic bond

Polar covalent bond

Nonpolar covalent bond

Hydrophobic interaction (force between hydrophobic molecules that causes oil to separate from vinegar solutions)

Polar covalent bonds are associated with molecules that are soluble in water. In a polar covalent bond, electrons are shared unequally between atoms, creating partial positive and negative charges. Water is a polar molecule, with a slightly positive hydrogen end and a slightly negative oxygen end. When a molecule with polar covalent bonds comes into contact with water, the positive end of water attracts the negative end of the molecule and vice versa. This allows the molecule to dissolve in water, making it soluble and preventing it from precipitating.

Explanation

Polar covalent bonds are associated with molecules that are soluble in water. In a polar covalent bond, electrons are shared unequally between atoms, creating partial positive and negative charges. Water is a polar molecule, with a slightly positive hydrogen end and a slightly negative oxygen end. When a molecule with polar covalent bonds comes into contact with water, the positive end of water attracts the negative end of the molecule and vice versa. This allows the molecule to dissolve in water, making it soluble and preventing it from precipitating.

48. Chemical processes that occur within a living organism in order to maintain life

Metabolism refers to the chemical processes that take place within a living organism to maintain life. It involves the conversion of food into energy, the synthesis of molecules necessary for growth and repair, and the breakdown of waste products. Metabolism is essential for various biological functions such as digestion, respiration, and circulation. It allows organisms to obtain energy from nutrients and regulate their internal environment. Overall, metabolism is a vital process that sustains life by ensuring the proper functioning of cells and tissues.

Explanation

Metabolism refers to the chemical processes that take place within a living organism to maintain life. It involves the conversion of food into energy, the synthesis of molecules necessary for growth and repair, and the breakdown of waste products. Metabolism is essential for various biological functions such as digestion, respiration, and circulation. It allows organisms to obtain energy from nutrients and regulate their internal environment. Overall, metabolism is a vital process that sustains life by ensuring the proper functioning of cells and tissues.

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49. Categorize the types of cholesterol...

delivers cholesterol to tissues/cells

returns excess cholesterol to Liver

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50. Misfolding of polypeptides is a serious problem in cells. Which of the following diseases are associated with an accumulation of misfolded polypeptides?

Alzheimer's and Parkinson's only

Parkinson's

Alzheimer's

Alzheimer's, Parkinson's, and diabetes mellitus

Diabetes mellitus only

Alzheimer's and Parkinson's diseases are both neurodegenerative disorders characterized by the accumulation of misfolded proteins in the brain. In Alzheimer's disease, beta-amyloid plaques and tau tangles form due to the misfolding of amyloid beta and tau proteins, respectively. In Parkinson's disease, misfolded alpha-synuclein protein aggregates form Lewy bodies, which are found in neurons. Diabetes mellitus is not directly associated with the accumulation of misfolded polypeptides.

Explanation

Alzheimer's and Parkinson's diseases are both neurodegenerative disorders characterized by the accumulation of misfolded proteins in the brain. In Alzheimer's disease, beta-amyloid plaques and tau tangles form due to the misfolding of amyloid beta and tau proteins, respectively. In Parkinson's disease, misfolded alpha-synuclein protein aggregates form Lewy bodies, which are found in neurons. Diabetes mellitus is not directly associated with the accumulation of misfolded polypeptides.

51. Characteristics of DNA:

Deoxyribose sugar

Ribose sugar

Adenine

Thymine

Double strands

Cytosine

Guanine

Missing an oxygen (hydroxyl group)

One more oxygen (hydroxyl group)

Uracil

Single strand

DNA, or deoxyribonucleic acid, is a molecule that contains the genetic instructions for the development and functioning of living organisms. It is composed of several components, including deoxyribose sugar, adenine, thymine, cytosine, and guanine. The deoxyribose sugar is a key component of DNA, providing the backbone for the molecule. Adenine, thymine, cytosine, and guanine are nitrogenous bases that pair up with each other to form the rungs of the DNA ladder. DNA is known for its double-stranded structure, with the two strands being held together by hydrogen bonds between the nitrogenous bases. Additionally, DNA is missing an oxygen group on the second carbon of the sugar, distinguishing it from ribose sugar found in RNA.

Explanation

DNA, or deoxyribonucleic acid, is a molecule that contains the genetic instructions for the development and functioning of living organisms. It is composed of several components, including deoxyribose sugar, adenine, thymine, cytosine, and guanine. The deoxyribose sugar is a key component of DNA, providing the backbone for the molecule. Adenine, thymine, cytosine, and guanine are nitrogenous bases that pair up with each other to form the rungs of the DNA ladder. DNA is known for its double-stranded structure, with the two strands being held together by hydrogen bonds between the nitrogenous bases. Additionally, DNA is missing an oxygen group on the second carbon of the sugar, distinguishing it from ribose sugar found in RNA.

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52. The semi-fluid substance in the cytoplasm

Cytosol refers to the semi-fluid substance present in the cytoplasm of a cell. It is the liquid component of the cytoplasm, excluding any organelles or other insoluble components. Cytosol is responsible for various cellular functions such as metabolism, transportation of molecules, and providing a medium for chemical reactions to occur. It contains various ions, proteins, and other molecules necessary for cellular processes.

Explanation

Cytosol refers to the semi-fluid substance present in the cytoplasm of a cell. It is the liquid component of the cytoplasm, excluding any organelles or other insoluble components. Cytosol is responsible for various cellular functions such as metabolism, transportation of molecules, and providing a medium for chemical reactions to occur. It contains various ions, proteins, and other molecules necessary for cellular processes.

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53. Match the following:

unique three-dimensional shape of the fully folded polypeptide.

regular patterns of hydrogen bonds (twisty telephone cord)

interact side by side (looks like folded up map)

overall protein structure resulting from the aggregation of two or more polypeptide subunits.

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54. Which of the following is an example of hydrolysis?

The reaction of two monosaccharides, forming a disaccharide with the release of water

The synthesis of two amino acids, forming a peptide with the release of water

The reaction of a fat, forming glycerol and fatty acids with the release of water

The reaction of a fat, forming glycerol and fatty acids with the consumption of water

not-available-via-ai

Explanation

not-available-via-ai

55. What determines a protein's function?

Its shape

The nucleotides

The ribosomes

Its polarity

The shape of a protein determines its function. Proteins are made up of long chains of amino acids that fold into specific shapes. These shapes are crucial for the protein to interact with other molecules and perform its specific function in the body. Different shapes allow proteins to bind to specific targets, catalyze reactions, transport molecules, and carry out various cellular processes. Therefore, the shape of a protein is a critical factor in determining its function.

Explanation

The shape of a protein determines its function. Proteins are made up of long chains of amino acids that fold into specific shapes. These shapes are crucial for the protein to interact with other molecules and perform its specific function in the body. Different shapes allow proteins to bind to specific targets, catalyze reactions, transport molecules, and carry out various cellular processes. Therefore, the shape of a protein is a critical factor in determining its function.

56.

What is the chemical reaction mechanism by which cells make polymers from monomers?

The formation of disulfide bridges between monomer

Phosphodiester linkages

Ionic bonding of monomers

Dehydration reactions

Dehydration reactions involve the removal of water molecules from monomers, allowing them to form covalent bonds and create polymers. This process is commonly seen in the synthesis of biological macromolecules such as proteins, nucleic acids, and carbohydrates. By eliminating water, cells can link monomers together and form larger, more complex structures necessary for various cellular functions.

Explanation

Dehydration reactions involve the removal of water molecules from monomers, allowing them to form covalent bonds and create polymers. This process is commonly seen in the synthesis of biological macromolecules such as proteins, nucleic acids, and carbohydrates. By eliminating water, cells can link monomers together and form larger, more complex structures necessary for various cellular functions.

57. These components of the endomembrane systems are either continuous or connected via transfer by _____.

The components of the endomembrane system, such as the endoplasmic reticulum, Golgi apparatus, and lysosomes, are either continuous or connected through the transfer of vesicles. Vesicles are small membrane-bound sacs that transport molecules between different compartments of the endomembrane system. They bud off from one organelle and fuse with another, allowing for the transfer of proteins, lipids, and other molecules. This continuous flow of vesicles helps maintain the integrity and functionality of the endomembrane system.

Explanation

The components of the endomembrane system, such as the endoplasmic reticulum, Golgi apparatus, and lysosomes, are either continuous or connected through the transfer of vesicles. Vesicles are small membrane-bound sacs that transport molecules between different compartments of the endomembrane system. They bud off from one organelle and fuse with another, allowing for the transfer of proteins, lipids, and other molecules. This continuous flow of vesicles helps maintain the integrity and functionality of the endomembrane system.

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58. Nitrogen (N) normally forms only three covalent bonds because it has a valence of five. However, ammonium has four covalent bonds, each to a different hydrogen (H) atom (H has a valence of one). Make a sketch of this molecule. Count the number of electrons in your sketch. Compare this number to the number of valence electrons in one N and four H's. What do you predict to be the charge on this molecule?

+1

-2

-1

+2

+3

Ammonium (NH4+) has four covalent bonds, with each hydrogen atom forming a bond with the nitrogen atom. Nitrogen has a valence of five, meaning it can form up to five covalent bonds. The sketch of the molecule would show the nitrogen atom in the center, with four hydrogen atoms surrounding it, each connected by a single bond.

To count the number of electrons in the sketch, we add up the valence electrons of each atom. Nitrogen has five valence electrons, and each hydrogen atom has one valence electron. So, the total number of electrons in the sketch would be 5 (from nitrogen) + 4 (from four hydrogen atoms) = 9.

Since the molecule has one more proton (positive charge) than electrons, the molecule will have a net positive charge of +1.

Explanation

Ammonium (NH4+) has four covalent bonds, with each hydrogen atom forming a bond with the nitrogen atom. Nitrogen has a valence of five, meaning it can form up to five covalent bonds. The sketch of the molecule would show the nitrogen atom in the center, with four hydrogen atoms surrounding it, each connected by a single bond.

To count the number of electrons in the sketch, we add up the valence electrons of each atom. Nitrogen has five valence electrons, and each hydrogen atom has one valence electron. So, the total number of electrons in the sketch would be 5 (from nitrogen) + 4 (from four hydrogen atoms) = 9.

Since the molecule has one more proton (positive charge) than electrons, the molecule will have a net positive charge of +1.

59. Compounds only consisted of carbon and hydrogen

The given answer is hydrocarbon, hydrocarbons. This is because compounds that consist only of carbon and hydrogen are called hydrocarbons. Hydrocarbons are organic compounds that are the building blocks of many important substances, such as fuels and plastics. They are composed of carbon atoms bonded together in chains or rings, with hydrogen atoms attached to the carbon atoms. The term "hydrocarbons" is used in the plural form because there are many different types and structures of hydrocarbon compounds.

Explanation

The given answer is hydrocarbon, hydrocarbons. This is because compounds that consist only of carbon and hydrogen are called hydrocarbons. Hydrocarbons are organic compounds that are the building blocks of many important substances, such as fuels and plastics. They are composed of carbon atoms bonded together in chains or rings, with hydrogen atoms attached to the carbon atoms. The term "hydrocarbons" is used in the plural form because there are many different types and structures of hydrocarbon compounds.

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60. Characteristics of RNA:

Ribose sugar

Adenine

Uracil

Cytosine

Thymine

Guanine

Has one more oxygen (hydroxyl group)

Single strands

Double strands

Has one less oxygen (hydroxyl group)

Deoxyribose sugar

RNA is a type of nucleic acid that contains ribose sugar, which is one of its characteristic features. It also consists of the nitrogenous bases adenine, uracil, cytosine, and guanine. Unlike DNA, RNA has one more oxygen (hydroxyl group) attached to its ribose sugar, giving it a slightly different structure. Another characteristic of RNA is that it typically exists as single strands, whereas DNA can form double strands. Therefore, the given answer correctly identifies the characteristics of RNA.

Explanation

RNA is a type of nucleic acid that contains ribose sugar, which is one of its characteristic features. It also consists of the nitrogenous bases adenine, uracil, cytosine, and guanine. Unlike DNA, RNA has one more oxygen (hydroxyl group) attached to its ribose sugar, giving it a slightly different structure. Another characteristic of RNA is that it typically exists as single strands, whereas DNA can form double strands. Therefore, the given answer correctly identifies the characteristics of RNA.

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61. How many molecules of water are needed to completely hydrolyze a polymer that is 11 monomers long?

10

5

6

11

To completely hydrolyze a polymer that is 11 monomers long, each monomer needs to be broken down by a water molecule. Since there are 11 monomers, we need 11 water molecules to fully hydrolyze the polymer. Therefore, the correct answer is 11.

Explanation

To completely hydrolyze a polymer that is 11 monomers long, each monomer needs to be broken down by a water molecule. Since there are 11 monomers, we need 11 water molecules to fully hydrolyze the polymer. Therefore, the correct answer is 11.

62. Bacteria has...

Cillia

Flagella

Cell wall

Large number of organelles

No separate organelles floating around

Membrane bound organelles

Bacteria have cilia and flagella, which are appendages that help with movement. They also have a cell wall, which provides support and protection. Unlike eukaryotic cells, bacteria do not have separate organelles floating around in their cytoplasm. Instead, their cellular functions are carried out by various structures and molecules within the cytoplasm. Bacteria do not have membrane-bound organelles like eukaryotic cells do. Therefore, the correct answer is cilia, flagella, cell wall, and no separate organelles floating around.

Explanation

Bacteria have cilia and flagella, which are appendages that help with movement. They also have a cell wall, which provides support and protection. Unlike eukaryotic cells, bacteria do not have separate organelles floating around in their cytoplasm. Instead, their cellular functions are carried out by various structures and molecules within the cytoplasm. Bacteria do not have membrane-bound organelles like eukaryotic cells do. Therefore, the correct answer is cilia, flagella, cell wall, and no separate organelles floating around.

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63. Water is less dense as a solid than as a liquid.

True

False

Water is less dense as a solid than as a liquid due to its unique molecular structure. When water freezes, the molecules arrange themselves in a lattice structure with open spaces between them. This causes the solid form of water, which is ice, to have a lower density than its liquid form. This is why ice floats on water. In contrast, when water is in its liquid state, the molecules are closer together, resulting in a higher density.

Explanation

Water is less dense as a solid than as a liquid due to its unique molecular structure. When water freezes, the molecules arrange themselves in a lattice structure with open spaces between them. This causes the solid form of water, which is ice, to have a lower density than its liquid form. This is why ice floats on water. In contrast, when water is in its liquid state, the molecules are closer together, resulting in a higher density.

64.

In a normal cellular protein, where would you expect to find a hydrophobic amino acid such as valine?

In the interior of the folded protein, away from water

Anywhere in the protein, with equal probability

In the transmembrane portion interacting with lipid fatty acid chains

On the exterior surface of the protein, interacting with water

Hydrophobic amino acids, such as valine, are nonpolar and repel water molecules. Therefore, they tend to be found in regions of a protein that are shielded from water, such as the interior of the folded protein. Additionally, hydrophobic amino acids can also be found in the transmembrane portion of proteins, where they interact with the hydrophobic lipid fatty acid chains of the cell membrane. Therefore, the correct answer is that valine can be found in the interior of the folded protein, away from water, or in a transmembrane portion interacting with lipid fatty acid chains.

Explanation

Hydrophobic amino acids, such as valine, are nonpolar and repel water molecules. Therefore, they tend to be found in regions of a protein that are shielded from water, such as the interior of the folded protein. Additionally, hydrophobic amino acids can also be found in the transmembrane portion of proteins, where they interact with the hydrophobic lipid fatty acid chains of the cell membrane. Therefore, the correct answer is that valine can be found in the interior of the folded protein, away from water, or in a transmembrane portion interacting with lipid fatty acid chains.

65. Which type of interaction stabilizes the α helix and the β pleated sheet structures of proteins?

Hydrogen bonds

Ionic bonds

Peptide bonds

Covalent bonds

Disulfide bonds

Hydrophobic interactions

Hydrogen bonds are responsible for stabilizing the α helix and β pleated sheet structures of proteins. These bonds occur between the hydrogen atom of one amino acid and the oxygen or nitrogen atom of another amino acid. The hydrogen bond is a relatively weak bond, but when many hydrogen bonds are present in a protein structure, they collectively provide stability and help maintain the secondary structure of the protein.

Explanation

Hydrogen bonds are responsible for stabilizing the α helix and β pleated sheet structures of proteins. These bonds occur between the hydrogen atom of one amino acid and the oxygen or nitrogen atom of another amino acid. The hydrogen bond is a relatively weak bond, but when many hydrogen bonds are present in a protein structure, they collectively provide stability and help maintain the secondary structure of the protein.

66. Which of the following are polysaccharides...

Glycogen

Lactose

Chitin

Cellulose

Starch

Glycogen, chitin, cellulose, and starch are all examples of polysaccharides. Polysaccharides are complex carbohydrates composed of multiple sugar units bonded together. Glycogen is a polysaccharide found in animals and serves as a storage form of glucose. Chitin is a polysaccharide found in the exoskeleton of insects and crustaceans, as well as in the cell walls of fungi. Cellulose is a polysaccharide found in the cell walls of plants and provides structural support. Starch is a polysaccharide found in plants and serves as a storage form of glucose.

Explanation

Glycogen, chitin, cellulose, and starch are all examples of polysaccharides. Polysaccharides are complex carbohydrates composed of multiple sugar units bonded together. Glycogen is a polysaccharide found in animals and serves as a storage form of glucose. Chitin is a polysaccharide found in the exoskeleton of insects and crustaceans, as well as in the cell walls of fungi. Cellulose is a polysaccharide found in the cell walls of plants and provides structural support. Starch is a polysaccharide found in plants and serves as a storage form of glucose.

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67. What is the order of the central dogma of biology? _____ undergoes _____ to turn into _____, which then undergoes _____ to form _____.

The central dogma of biology states that DNA undergoes transcription to turn into mRNA, which then undergoes translation to form proteins. Transcription is the process of creating an RNA copy of a DNA sequence, while translation is the process of using the mRNA sequence to synthesize a protein. Therefore, the correct order is DNA, transcription, mRNA, translation, proteins.

Explanation

The central dogma of biology states that DNA undergoes transcription to turn into mRNA, which then undergoes translation to form proteins. Transcription is the process of creating an RNA copy of a DNA sequence, while translation is the process of using the mRNA sequence to synthesize a protein. Therefore, the correct order is DNA, transcription, mRNA, translation, proteins.

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68. Genes are

Segments of the chromosome that contain the instructions to make protein

Found in the nucleus of the cell

Pieces of DNA

All the options

Genes are segments of the chromosome that contain the instructions to make proteins. They are found in the nucleus of the cell and are made up of pieces of DNA. Therefore, all the given options accurately describe genes.

Explanation

Genes are segments of the chromosome that contain the instructions to make proteins. They are found in the nucleus of the cell and are made up of pieces of DNA. Therefore, all the given options accurately describe genes.

69. A molecule with the chemical formula C6H12O6 is probably a

Carbohydrate

Monosaccharide

Fatty acid

Disaccharide

Polysaccharide

Protein

Lipids

A molecule with the chemical formula C6H12O6 is most likely a carbohydrate because carbohydrates are organic compounds made up of carbon, hydrogen, and oxygen atoms. Monosaccharides are the simplest form of carbohydrates and have the general formula (CH2O)n, where n is usually between 3 and 7. C6H12O6 fits this general formula and is therefore a monosaccharide. Fatty acids, disaccharides, polysaccharides, proteins, and lipids do not have the same chemical formula as C6H12O6, so they are not the correct answer.

Explanation

A molecule with the chemical formula C6H12O6 is most likely a carbohydrate because carbohydrates are organic compounds made up of carbon, hydrogen, and oxygen atoms. Monosaccharides are the simplest form of carbohydrates and have the general formula (CH2O)n, where n is usually between 3 and 7. C6H12O6 fits this general formula and is therefore a monosaccharide. Fatty acids, disaccharides, polysaccharides, proteins, and lipids do not have the same chemical formula as C6H12O6, so they are not the correct answer.

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70. The atomic number of an atom is defined as

The number of protons and neutrons in the nucleus

The number of electrons in outermost shell

The number of protons in the nucleus

Total number of electrons and neutrons

Number of energy shells

Arrangement of neutrons in nucleus

The atomic number of an atom is defined as the number of protons in the nucleus. This is because the atomic number determines the element and its properties. The number of protons in an atom's nucleus is unique to each element and determines its identity on the periodic table.

Explanation

The atomic number of an atom is defined as the number of protons in the nucleus. This is because the atomic number determines the element and its properties. The number of protons in an atom's nucleus is unique to each element and determines its identity on the periodic table.

71. Functions of lysosomes:

Autophagy

Phagocytosis

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72. What is released every time amino acids bond?

When amino acids bond, a process called dehydration synthesis occurs, where a water molecule is released. This happens because one amino acid donates a hydrogen atom (H) and the other donates a hydroxyl group (OH), resulting in the formation of a covalent bond between the two amino acids. The hydrogen atom and hydroxyl group combine to form a water molecule (H2O), which is released as a byproduct of the bonding process.

Explanation

When amino acids bond, a process called dehydration synthesis occurs, where a water molecule is released. This happens because one amino acid donates a hydrogen atom (H) and the other donates a hydroxyl group (OH), resulting in the formation of a covalent bond between the two amino acids. The hydrogen atom and hydroxyl group combine to form a water molecule (H2O), which is released as a byproduct of the bonding process.

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73. Sickle-cell disease is caused by a mutation in the beta-hemoglobin gene that changes a charged amino acid, glutamic acid, to valine, a hydrophobic amino acid. Where in the protein would you expect to find glutamic acid?

On the exterior surface of the cell.

On the interior surface of the cell

In the nucleus

In the blood

In water

If something is going to be in contact with water, the polarity of the molecule will be on the exterior surface of the protein.

Explanation

If something is going to be in contact with water, the polarity of the molecule will be on the exterior surface of the protein.

74. A molecule with the formula C₁₈H₃₆O₂ is probably a

Amino acid

Carbohydrate

Sugar

Fatty acid

Protein

Nucleic acid

Hydrocarbon

A molecule with the formula C18H36O2 is likely a fatty acid because it contains a long chain of carbon atoms (C18) with hydrogen atoms attached to them (H36), along with two oxygen atoms (O2). Fatty acids are organic compounds that are an important component of lipids, which are essential for energy storage and insulation in organisms. They are characterized by their long hydrocarbon chains with a carboxyl group (COOH) at one end.

Explanation

A molecule with the formula C18H36O2 is likely a fatty acid because it contains a long chain of carbon atoms (C18) with hydrogen atoms attached to them (H36), along with two oxygen atoms (O2). Fatty acids are organic compounds that are an important component of lipids, which are essential for energy storage and insulation in organisms. They are characterized by their long hydrocarbon chains with a carboxyl group (COOH) at one end.

75. Which of the following statements concerning saturated fats is not true?

They are one of several factors that contribute to heart disease.

They contain more hydrogen than unsaturated fats having the same number of carbon atoms.

They generally solidify at room temperature.

They have multiple double bonds in the carbon chains of their fatty acids.

Saturated fats are known to contribute to heart disease, contain more hydrogen than unsaturated fats with the same number of carbon atoms, and generally solidify at room temperature. However, they do not have multiple double bonds in the carbon chains of their fatty acids. Instead, saturated fats have single bonds between all carbon atoms, which is why they are "saturated" with hydrogen atoms. This lack of double bonds makes them less prone to oxidation and more stable.

Explanation

Saturated fats are known to contribute to heart disease, contain more hydrogen than unsaturated fats with the same number of carbon atoms, and generally solidify at room temperature. However, they do not have multiple double bonds in the carbon chains of their fatty acids. Instead, saturated fats have single bonds between all carbon atoms, which is why they are "saturated" with hydrogen atoms. This lack of double bonds makes them less prone to oxidation and more stable.

76. Which of the following are disaccharides?

Sucrose

Lactose

Maltose

Starch

Glucose

Galactose

Sucrose, lactose, and maltose are all examples of disaccharides. Disaccharides are carbohydrates composed of two monosaccharide units joined together by a glycosidic bond. Sucrose is made up of glucose and fructose, lactose is made up of glucose and galactose, and maltose is made up of two glucose molecules. Starch, glucose, and galactose are not disaccharides. Starch is a polysaccharide made up of many glucose units, while glucose and galactose are monosaccharides, which are single sugar units.

Explanation

Sucrose, lactose, and maltose are all examples of disaccharides. Disaccharides are carbohydrates composed of two monosaccharide units joined together by a glycosidic bond. Sucrose is made up of glucose and fructose, lactose is made up of glucose and galactose, and maltose is made up of two glucose molecules. Starch, glucose, and galactose are not disaccharides. Starch is a polysaccharide made up of many glucose units, while glucose and galactose are monosaccharides, which are single sugar units.

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77. DNA is located where in what kind of cell?

eukaryote

prokaryote

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78. How many bonds are formed with each nitrogenous bases?

Adenine and Thymine

Cytosine and Guanine

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79. _____ essential to the structures and functions of life,They are polymers built from various combinations of 20 amino acid monomers

Proteins are essential to the structures and functions of life. They are polymers built from various combinations of 20 amino acid monomers. This means that proteins are made up of long chains of amino acids, which are the building blocks of life. These chains can fold into complex three-dimensional structures, allowing proteins to carry out a wide range of functions in cells and organisms. Therefore, proteins are crucial for the proper functioning and survival of living organisms.

Explanation

Proteins are essential to the structures and functions of life. They are polymers built from various combinations of 20 amino acid monomers. This means that proteins are made up of long chains of amino acids, which are the building blocks of life. These chains can fold into complex three-dimensional structures, allowing proteins to carry out a wide range of functions in cells and organisms. Therefore, proteins are crucial for the proper functioning and survival of living organisms.

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80. Organelles that change energy from one form to another: (structure)

Specialized metabolic compartment bounded by a single membrane

two membranes around fluid stroma, which contains thylakoids stacked into a grana

Bounded by double membrane, inner membrane sac has infoldings (cristae)

*chloroplasts found in plant cells or cells of photosynthetic eukaryotes

Explanation

*chloroplasts found in plant cells or cells of photosynthetic eukaryotes

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81. On food packages, to what does the term insoluble fiber refer?

Cellulose

Polypeptides

Starch

Chitin

Amylopectin

Insoluble fiber refers to cellulose, which is a complex carbohydrate found in the cell walls of plants. It is not easily broken down by the digestive system and passes through the body relatively intact. Cellulose adds bulk to the stool and helps promote regular bowel movements. It also aids in preventing constipation and maintaining overall digestive health.

Explanation

Insoluble fiber refers to cellulose, which is a complex carbohydrate found in the cell walls of plants. It is not easily broken down by the digestive system and passes through the body relatively intact. Cellulose adds bulk to the stool and helps promote regular bowel movements. It also aids in preventing constipation and maintaining overall digestive health.

82. Which of the following are monosaccharides?

Glucose

Galactose

Lactose

Sucrose

Starch

Maltose

Fructose

The monosaccharides are the simplest form of carbohydrates and cannot be broken down into smaller sugar molecules. Glucose, galactose, and fructose are all monosaccharides because they consist of a single sugar unit. Lactose, sucrose, starch, and maltose, on the other hand, are not monosaccharides as they are composed of two or more sugar units.

Explanation

The monosaccharides are the simplest form of carbohydrates and cannot be broken down into smaller sugar molecules. Glucose, galactose, and fructose are all monosaccharides because they consist of a single sugar unit. Lactose, sucrose, starch, and maltose, on the other hand, are not monosaccharides as they are composed of two or more sugar units.

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83. Characteristics of Saturated Fats

Solidifies at room temperature

Forms single bonds only

Forms double bonds

Forms double bonds which create kinks

Has max amount of hydrogen bonded to carbons

Saturated fats are characterized by their ability to solidify at room temperature. This is because they have a higher melting point compared to unsaturated fats. They also form single bonds only, which means that all of the carbon atoms in the fatty acid chain are bonded to the maximum number of hydrogen atoms possible. This results in a straight and rigid structure, which contributes to their solid state. Additionally, saturated fats have the maximum amount of hydrogen bonded to carbons, further enhancing their stability and solidifying properties.

Explanation

Saturated fats are characterized by their ability to solidify at room temperature. This is because they have a higher melting point compared to unsaturated fats. They also form single bonds only, which means that all of the carbon atoms in the fatty acid chain are bonded to the maximum number of hydrogen atoms possible. This results in a straight and rigid structure, which contributes to their solid state. Additionally, saturated fats have the maximum amount of hydrogen bonded to carbons, further enhancing their stability and solidifying properties.

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84. Which of the following sequences has the highest melting temperature when hydrogen bonded to their complementary strands of DNA (i.e. melting temperature/breaking apart of double helix strands)?

CCGGCCGGCCAAT

CCGGCCGGCC

ATAAATCGTAG

TACGAATCTAT

Greater number of nucleotides = higher temperature to melt it
C-G bond is harder to break because extra hydrogen bond
But when doing melting point, more hydrogen bonds = more energy to break it = higher melting point needed

Explanation

Greater number of nucleotides = higher temperature to melt it
C-G bond is harder to break because extra hydrogen bond
But when doing melting point, more hydrogen bonds = more energy to break it = higher melting point needed

85. What is the cell theory?

All organisms made of cells.

Cells is the simplest collection of matter that can be alive.

All cells are related by descent from earlier cells.

Not every living thing is made of cells.

Cells are created spontaneously and not from previous cells.

The cell theory states that all organisms are made of cells, which means that cells are the basic building blocks of life. It also states that cells are the simplest collection of matter that can be alive, meaning that cells are the smallest unit of life. Additionally, the cell theory states that all cells are related by descent from earlier cells, implying that all cells come from pre-existing cells through cell division. This theory does not support the idea that living things can be made without cells or that cells can be created spontaneously.

Explanation

The cell theory states that all organisms are made of cells, which means that cells are the basic building blocks of life. It also states that cells are the simplest collection of matter that can be alive, meaning that cells are the smallest unit of life. Additionally, the cell theory states that all cells are related by descent from earlier cells, implying that all cells come from pre-existing cells through cell division. This theory does not support the idea that living things can be made without cells or that cells can be created spontaneously.

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86. In animal metabolism, most of the monomers released by digestion of food macromolecules are metabolized to provide energy. Only a small portion of these monomers are used for synthesis of new macromolecules. The net result is that

Water is consumed by animal metabolism

Water is not consumed by animal metabolism

Water is produced by animal metabolism

Water is not produced by animal metabolism

In animal metabolism, most of the monomers released by digestion of food macromolecules are metabolized to provide energy. This process involves breaking down the monomers into smaller molecules, which releases energy and produces waste products, including water. Therefore, water is consumed by animal metabolism as it is needed for various metabolic processes and is produced as a byproduct of these processes.

Explanation

In animal metabolism, most of the monomers released by digestion of food macromolecules are metabolized to provide energy. This process involves breaking down the monomers into smaller molecules, which releases energy and produces waste products, including water. Therefore, water is consumed by animal metabolism as it is needed for various metabolic processes and is produced as a byproduct of these processes.

87. Which of the following contain amino acids...

Enzymes

Cholesterol

Proteins

Antibodies

Insulin

Hemoglobin

Enzymes, proteins, antibodies, insulin, and hemoglobin all contain amino acids. Amino acids are the building blocks of proteins, and these substances are all types of proteins. Enzymes are a specific type of protein that act as catalysts in biochemical reactions. Antibodies are proteins produced by the immune system to help fight off foreign substances. Insulin is a hormone that regulates blood sugar levels and is made up of amino acids. Hemoglobin is a protein found in red blood cells that carries oxygen throughout the body. Cholesterol, on the other hand, is a type of lipid and does not contain amino acids.

Explanation

Enzymes, proteins, antibodies, insulin, and hemoglobin all contain amino acids. Amino acids are the building blocks of proteins, and these substances are all types of proteins. Enzymes are a specific type of protein that act as catalysts in biochemical reactions. Antibodies are proteins produced by the immune system to help fight off foreign substances. Insulin is a hormone that regulates blood sugar levels and is made up of amino acids. Hemoglobin is a protein found in red blood cells that carries oxygen throughout the body. Cholesterol, on the other hand, is a type of lipid and does not contain amino acids.

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88. Another term to say trans fat

Partially hydrogenated

Unsaturated

Oil at room temperature

Desaturated

The correct answer is "partially hydrogenated." Partially hydrogenated refers to a process where hydrogen is added to unsaturated fats, making them more solid at room temperature. This process creates trans fats, which are known to be unhealthy and increase the risk of heart disease. Therefore, partially hydrogenated is another term used to describe trans fat.

Explanation

The correct answer is "partially hydrogenated." Partially hydrogenated refers to a process where hydrogen is added to unsaturated fats, making them more solid at room temperature. This process creates trans fats, which are known to be unhealthy and increase the risk of heart disease. Therefore, partially hydrogenated is another term used to describe trans fat.

89. Which of the following statements regarding carbon is false?

Carbon has the capacity to form single and double bonds

Carbon has the ability to bond with up to four other atoms.

Carbon has a tendency to form covalent bonds

Carbon has the capacity to form polar bonds with hydrogen

Carbon has the ability to bond together to form extensive, branched, or unbranched carbon skeletons

Carbon actually has the capacity to form polar bonds with hydrogen. This is due to the difference in electronegativity between carbon and hydrogen, where carbon is slightly more electronegative. As a result, the carbon-hydrogen bond has a partial positive charge on the hydrogen atom and a partial negative charge on the carbon atom.

Explanation

Carbon actually has the capacity to form polar bonds with hydrogen. This is due to the difference in electronegativity between carbon and hydrogen, where carbon is slightly more electronegative. As a result, the carbon-hydrogen bond has a partial positive charge on the hydrogen atom and a partial negative charge on the carbon atom.

90. Proteins differ from one another because

Each protein contains its own unique sequence of sugar molecules.

The peptide bonds linking amino acids differ from protein to protein.

The primary structure in the polypeptide chain differs from protein to protein.

All proteins have different quaternary structure

Different tertiary structure based on beta pleated sheets and alpha helices

The primary structure in the polypeptide chain differs from protein to protein. This refers to the specific sequence of amino acids that make up a protein. Each protein has its own unique sequence, which is determined by the genetic code. This sequence determines the overall shape and function of the protein. Therefore, even though proteins may have similar secondary, tertiary, or quaternary structures, their primary structures will be different, leading to differences in their overall properties and functions.

Explanation

The primary structure in the polypeptide chain differs from protein to protein. This refers to the specific sequence of amino acids that make up a protein. Each protein has its own unique sequence, which is determined by the genetic code. This sequence determines the overall shape and function of the protein. Therefore, even though proteins may have similar secondary, tertiary, or quaternary structures, their primary structures will be different, leading to differences in their overall properties and functions.

91. Which of the following are nitrogenous bases of the purine type? (two ring)

Adenine

Cytosine

Uracil

Guanine

Thymine

Adenine and guanine are nitrogenous bases of the purine type because they have a two-ring structure. Cytosine, uracil, and thymine are nitrogenous bases of the pyrimidine type, as they have a single-ring structure.

Explanation

Adenine and guanine are nitrogenous bases of the purine type because they have a two-ring structure. Cytosine, uracil, and thymine are nitrogenous bases of the pyrimidine type, as they have a single-ring structure.

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92.

At which level of protein structure are interactions between the side chains (R groups) most important?

Quaternary

Tertiary

Primary

Secondary

In the tertiary level of protein structure, interactions between the side chains (R groups) are most important. This is because the tertiary structure is characterized by the folding of the polypeptide chain into a 3D shape, and the side chains play a crucial role in determining the specific folding pattern. The interactions between the side chains can include hydrogen bonding, disulfide bridges, hydrophobic interactions, and electrostatic attractions, which all contribute to the stability and functionality of the protein.

Explanation

In the tertiary level of protein structure, interactions between the side chains (R groups) are most important. This is because the tertiary structure is characterized by the folding of the polypeptide chain into a 3D shape, and the side chains play a crucial role in determining the specific folding pattern. The interactions between the side chains can include hydrogen bonding, disulfide bridges, hydrophobic interactions, and electrostatic attractions, which all contribute to the stability and functionality of the protein.

93. Categorize these polysaccharides:

storage polysaccharide composed of glucose monomers and found in plants

storage polysaccharide composed of glucose, which is hydrolyzed by animals when glucose is needed.

polymer of glucose that forms plant cell walls.

polysaccharide used by insects & crustaceans to build an exoskeleton

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94. Which of these molecules is not formed by dehydration reactions?

Amylose

Fatty acids

Disaccharides

Carbohydrates

DNA

Protein

Fatty acids are not formed by dehydration reactions. Dehydration reactions involve the removal of water molecules to form larger molecules. Amylose, disaccharides, carbohydrates, DNA, and proteins are all formed through dehydration reactions. However, fatty acids are formed through hydrolysis reactions, which involve the addition of water molecules to break down larger molecules. Therefore, fatty acids are the only molecule listed that is not formed by dehydration reactions.

Explanation

Fatty acids are not formed by dehydration reactions. Dehydration reactions involve the removal of water molecules to form larger molecules. Amylose, disaccharides, carbohydrates, DNA, and proteins are all formed through dehydration reactions. However, fatty acids are formed through hydrolysis reactions, which involve the addition of water molecules to break down larger molecules. Therefore, fatty acids are the only molecule listed that is not formed by dehydration reactions.

95. The dependent variable is what you manipulate.

True

False

Independent: what you manipulate to measure the dependent variable
Dependent: what you measure (depends on independent variable)

Explanation

Independent: what you manipulate to measure the dependent variable
Dependent: what you measure (depends on independent variable)

96. Insulin is a protein that is produced by pancreatic cells and secreted into the bloodstream. Which of the following choices best describes the route of insulin from its production to its exit from the cell?

Rough Endoplasmic Reticulum --> Golgi apparatus --> cell membrane

Golgi apparatus --> Rough Endoplasmic Reticulum --> cell membrane

Plasma membrane --> Golgi apparatus --> Rough Endoplasmic Reticulum

Rough Endoplasmic Reticulum --> cell membrane --> Golgi apparatus

Insulin is initially synthesized in the rough endoplasmic reticulum (ER), where it undergoes post-translational modifications. It is then transported to the Golgi apparatus, where further processing and packaging take place. Finally, the insulin-containing vesicles fuse with the cell membrane, allowing the release of insulin into the bloodstream.

Explanation

Insulin is initially synthesized in the rough endoplasmic reticulum (ER), where it undergoes post-translational modifications. It is then transported to the Golgi apparatus, where further processing and packaging take place. Finally, the insulin-containing vesicles fuse with the cell membrane, allowing the release of insulin into the bloodstream.

97. Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?

Dehydration reactions ionize water molecules and add hydroxyl groups to polymers; hydrolysis reactions release hydroxyl groups from polymers.

Hydrolysis creates monomers, and dehydration reactions break down polymers.

Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers.

Dehydration reactions can occur only after hydrolysis.

Dehydration reactions eliminate water from lipid membranes, and hydrolysis makes lipid membranes water permeable.

Dehydration reactions involve the removal of water molecules to form larger molecules, such as polymers. On the other hand, hydrolysis reactions break down polymers by adding water molecules. Therefore, the correct answer states that dehydration reactions assemble polymers, while hydrolysis reactions break down polymers.

Explanation

Dehydration reactions involve the removal of water molecules to form larger molecules, such as polymers. On the other hand, hydrolysis reactions break down polymers by adding water molecules. Therefore, the correct answer states that dehydration reactions assemble polymers, while hydrolysis reactions break down polymers.

98. How does RNA differ from DNA?

DNA forms duplexes (double strands); RNA does not.

DNA encodes heredity information; RNA does not.

DNA contains thymine, RNA contains uracil.

All of the above

RNA differs from DNA because RNA contains uracil instead of thymine. DNA and RNA both contain adenine, cytosine, and guanine, but DNA exclusively contains thymine while RNA exclusively contains uracil. This difference in base pairs is one of the key distinctions between DNA and RNA.

Explanation

RNA differs from DNA because RNA contains uracil instead of thymine. DNA and RNA both contain adenine, cytosine, and guanine, but DNA exclusively contains thymine while RNA exclusively contains uracil. This difference in base pairs is one of the key distinctions between DNA and RNA.

99. Which of the following is a polymer?

Cellulose

Chitin

DNA

Glucose

Starch

All of the options listed (cellulose, chitin, DNA, and starch) are polymers. A polymer is a large molecule composed of repeating subunits called monomers. Cellulose and chitin are both polysaccharides, which are polymers made up of sugar monomers. DNA is a nucleic acid polymer made up of nucleotide monomers. Starch is also a polysaccharide made up of glucose monomers. Therefore, all of the options provided are examples of polymers.

Explanation

All of the options listed (cellulose, chitin, DNA, and starch) are polymers. A polymer is a large molecule composed of repeating subunits called monomers. Cellulose and chitin are both polysaccharides, which are polymers made up of sugar monomers. DNA is a nucleic acid polymer made up of nucleotide monomers. Starch is also a polysaccharide made up of glucose monomers. Therefore, all of the options provided are examples of polymers.

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100. Which elements are the most electronegative (polar) in the body?

Carbon

Nitrogen

Oxygen

Hydrogen

Nitrogen and oxygen are the most electronegative elements in the body. Electronegativity is a measure of an atom's ability to attract electrons towards itself in a chemical bond. Nitrogen and oxygen have higher electronegativity values compared to carbon and hydrogen. This means that nitrogen and oxygen atoms have a stronger pull on the shared electrons in a chemical bond, resulting in a more polar bond. In the body, nitrogen and oxygen play important roles in various biological processes, including protein synthesis, respiration, and DNA replication.

Explanation

Nitrogen and oxygen are the most electronegative elements in the body. Electronegativity is a measure of an atom's ability to attract electrons towards itself in a chemical bond. Nitrogen and oxygen have higher electronegativity values compared to carbon and hydrogen. This means that nitrogen and oxygen atoms have a stronger pull on the shared electrons in a chemical bond, resulting in a more polar bond. In the body, nitrogen and oxygen play important roles in various biological processes, including protein synthesis, respiration, and DNA replication.

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101. What type of covalent bond between amino acid side chains (R groups) functions in maintaining a polypeptide's specific three-dimensional shape?

Hydrophobic interaction

Ionic bond

Hydrogen bond

Disulfide bond

Covalent bond

Disulfide bonds are covalent bonds formed between two cysteine amino acid residues. These bonds play a crucial role in maintaining a polypeptide's specific three-dimensional shape by stabilizing the protein structure. Disulfide bonds form when two cysteine residues come close together and undergo oxidation, resulting in the formation of a covalent bond between their sulfur atoms. This bond helps to hold different regions of the polypeptide together, contributing to the overall stability and shape of the protein.

Explanation

Disulfide bonds are covalent bonds formed between two cysteine amino acid residues. These bonds play a crucial role in maintaining a polypeptide's specific three-dimensional shape by stabilizing the protein structure. Disulfide bonds form when two cysteine residues come close together and undergo oxidation, resulting in the formation of a covalent bond between their sulfur atoms. This bond helps to hold different regions of the polypeptide together, contributing to the overall stability and shape of the protein.

102.

An atom has six electrons in its valence shell. How many single covalent bonds would you expect it to form in most circumstances?

2

3

4

6

1

An atom with six electrons in its valence shell would typically form two single covalent bonds in most circumstances. This is because each covalent bond involves the sharing of two electrons, and with six valence electrons, the atom can share two electrons with two other atoms to form two bonds.

Explanation

An atom with six electrons in its valence shell would typically form two single covalent bonds in most circumstances. This is because each covalent bond involves the sharing of two electrons, and with six valence electrons, the atom can share two electrons with two other atoms to form two bonds.

103. A particular nucleotide sequence that can instruct the formation of a polypeptide is called _____.

A particular nucleotide sequence that can instruct the formation of a polypeptide is called a gene. Genes are segments of DNA that contain the instructions for building proteins, which are essential for the structure and function of cells. These instructions are encoded in the nucleotide sequence of the gene and are transcribed into mRNA, which is then translated into a polypeptide during protein synthesis. Therefore, a gene is the fundamental unit of heredity and plays a crucial role in determining the characteristics and traits of an organism.

Explanation

A particular nucleotide sequence that can instruct the formation of a polypeptide is called a gene. Genes are segments of DNA that contain the instructions for building proteins, which are essential for the structure and function of cells. These instructions are encoded in the nucleotide sequence of the gene and are transcribed into mRNA, which is then translated into a polypeptide during protein synthesis. Therefore, a gene is the fundamental unit of heredity and plays a crucial role in determining the characteristics and traits of an organism.

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104. Components of Endomembrane System:

ER

Golgi Body

Lysosomes

Vacuoles

Nuclear Envelope

Plasma membranes

Cell wall

Ribosomes

The endomembrane system is a network of membranes within a eukaryotic cell that is involved in the synthesis, processing, and transport of proteins and lipids. It includes the endoplasmic reticulum (ER), Golgi body, lysosomes, vacuoles, nuclear envelope, and plasma membranes. These components work together to ensure the proper functioning of the cell. The ER is responsible for protein synthesis and lipid metabolism, while the Golgi body modifies and packages proteins for transport. Lysosomes contain enzymes for intracellular digestion, vacuoles store substances, the nuclear envelope encloses the nucleus, and plasma membranes control the exchange of materials with the surroundings.

Explanation

The endomembrane system is a network of membranes within a eukaryotic cell that is involved in the synthesis, processing, and transport of proteins and lipids. It includes the endoplasmic reticulum (ER), Golgi body, lysosomes, vacuoles, nuclear envelope, and plasma membranes. These components work together to ensure the proper functioning of the cell. The ER is responsible for protein synthesis and lipid metabolism, while the Golgi body modifies and packages proteins for transport. Lysosomes contain enzymes for intracellular digestion, vacuoles store substances, the nuclear envelope encloses the nucleus, and plasma membranes control the exchange of materials with the surroundings.

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105. Lipids are good for _____.

However, lipids are good for storage. The fact that they are insoluble in water makes helps in this cause, and also they can provide twice as much energy (or more) as some carbohydrates.

Explanation

However, lipids are good for storage. The fact that they are insoluble in water makes helps in this cause, and also they can provide twice as much energy (or more) as some carbohydrates.

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106. What are the macromolecules of life?

Lipids (fats)

Steroids

Protein

Carbohydrates

Sugars

Nucleic Acids

Glycerol

The macromolecules of life are lipids (fats), proteins, carbohydrates, and nucleic acids. Lipids are important for energy storage and insulation. Proteins are involved in various cellular functions and are made up of amino acids. Carbohydrates are a major source of energy for the body and include sugars. Nucleic acids, such as DNA and RNA, store and transmit genetic information.

Explanation

The macromolecules of life are lipids (fats), proteins, carbohydrates, and nucleic acids. Lipids are important for energy storage and insulation. Proteins are involved in various cellular functions and are made up of amino acids. Carbohydrates are a major source of energy for the body and include sugars. Nucleic acids, such as DNA and RNA, store and transmit genetic information.

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107. Match organelle to its function:

Mitochondria

Cytoskeleton

Nucleus

Smooth ER

Rough ER

Golgi Apparatus

Chromatin

Ribosomes

Lysosomes

Chloroplasts

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109.

The molecular formula for glucose is C₆H₁₂O₆. What would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions?

C3H6O3

C18H32O16

C18H10O15

C6H10O5

C18H36O18

When three glucose molecules are linked together by dehydration reactions, a water molecule is removed for each linkage. Since there are three glucose molecules, three water molecules are removed in total. The molecular formula for glucose is C6H12O6, so each glucose molecule contributes 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms. Therefore, when three glucose molecules are linked together, the resulting molecule would have 18 carbon atoms, 32 hydrogen atoms, and 16 oxygen atoms, which corresponds to the molecular formula C18H32O16.

Explanation

When three glucose molecules are linked together by dehydration reactions, a water molecule is removed for each linkage. Since there are three glucose molecules, three water molecules are removed in total. The molecular formula for glucose is C6H12O6, so each glucose molecule contributes 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms. Therefore, when three glucose molecules are linked together, the resulting molecule would have 18 carbon atoms, 32 hydrogen atoms, and 16 oxygen atoms, which corresponds to the molecular formula C18H32O16.

110.

When the atoms involved in a covalent bond have the same electronegativity, what type of bond results?

Ionic bond

Polar covalent bond

Nonpolar covalent bond

Hydrogen bond

When the atoms involved in a covalent bond have the same electronegativity, it means that they have an equal pull for the shared electrons. This results in a nonpolar covalent bond, where the electrons are shared equally between the atoms. In this type of bond, there is no separation of charge and the molecule is symmetrical.

Explanation

When the atoms involved in a covalent bond have the same electronegativity, it means that they have an equal pull for the shared electrons. This results in a nonpolar covalent bond, where the electrons are shared equally between the atoms. In this type of bond, there is no separation of charge and the molecule is symmetrical.

111. Functions of Smooth ER:

Modified and packages proteins

Stores calcium ions

Detoxifies drugs & poisons

Transport vesicle that is budded off and sends to Golgi Apparatus

Synthesizes lipids

Metabolizes carbohydrates

The smooth endoplasmic reticulum (ER) has several functions. It stores calcium ions, which are important for various cellular processes such as muscle contraction and cell signaling. It also detoxifies drugs and poisons by metabolizing them into less harmful substances. The smooth ER synthesizes lipids, which are essential components of cell membranes and play a role in hormone production. Additionally, it metabolizes carbohydrates, converting them into energy or storing them for later use.

Explanation

The smooth endoplasmic reticulum (ER) has several functions. It stores calcium ions, which are important for various cellular processes such as muscle contraction and cell signaling. It also detoxifies drugs and poisons by metabolizing them into less harmful substances. The smooth ER synthesizes lipids, which are essential components of cell membranes and play a role in hormone production. Additionally, it metabolizes carbohydrates, converting them into energy or storing them for later use.

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112.

The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are the α form. Which of the following could amylase break down?

Glycogen

Cellulose

Starch

Chitin

Amylase is an enzyme that specifically breaks down glycosidic linkages between glucose monomers. Glycogen is a polysaccharide composed of glucose monomers linked together by glycosidic bonds, and these glucose monomers are in the α form. Therefore, amylase can break down glycogen by breaking the glycosidic linkages between the α-glucose monomers. On the other hand, cellulose, starch, and chitin consist of glucose monomers linked together by glycosidic bonds, but the glucose monomers in these polysaccharides are in the β form. Since amylase can only break glycosidic linkages between glucose monomers in the α form, it cannot break down cellulose, starch, or chitin.

Explanation

Amylase is an enzyme that specifically breaks down glycosidic linkages between glucose monomers. Glycogen is a polysaccharide composed of glucose monomers linked together by glycosidic bonds, and these glucose monomers are in the α form. Therefore, amylase can break down glycogen by breaking the glycosidic linkages between the α-glucose monomers. On the other hand, cellulose, starch, and chitin consist of glucose monomers linked together by glycosidic bonds, but the glucose monomers in these polysaccharides are in the β form. Since amylase can only break glycosidic linkages between glucose monomers in the α form, it cannot break down cellulose, starch, or chitin.

113. Polysaccharides, triacylglycerides, and proteins are similar in that they

Are synthesized from subunits by dehydration reactions

Are synthesized from subunits by hydrolysis reactions

Are synthesized from macromolecules by hydrolysis reactions

Are synthesized from macromolecules by dehydration reactions

Polysaccharides, triacylglycerides, and proteins are all macromolecules that are synthesized from smaller subunits. Dehydration reactions occur during the synthesis of these macromolecules, where water molecules are removed to form covalent bonds between the subunits. This process allows the subunits to join together and form larger molecules. Therefore, the correct answer is that polysaccharides, triacylglycerides, and proteins are synthesized from subunits by dehydration reactions.

Explanation

Polysaccharides, triacylglycerides, and proteins are all macromolecules that are synthesized from smaller subunits. Dehydration reactions occur during the synthesis of these macromolecules, where water molecules are removed to form covalent bonds between the subunits. This process allows the subunits to join together and form larger molecules. Therefore, the correct answer is that polysaccharides, triacylglycerides, and proteins are synthesized from subunits by dehydration reactions.

114. Characteristics of lysosomes:

Digests things by fusing with other vesicles and organelles

Membranous sac of hydrolytic enzymes that can digest macromolecules

They are enzymes can hydrolyze proteins, fats, polysaccharides, and nucleic acids

Transport budded off vesicles and sends to Golgi Apparatus

Metabolizes carbohydrates

Detoxifies drugs & poisons

Storage for water

Creates ATP to process metabolic reactions

Lysosomes are membranous sacs filled with hydrolytic enzymes that can break down macromolecules. These enzymes can hydrolyze proteins, fats, polysaccharides, and nucleic acids. Lysosomes also have the ability to fuse with other vesicles and organelles in order to digest their contents. Additionally, lysosomes are involved in the transport of budded off vesicles to the Golgi Apparatus. Lysosomes do not metabolize carbohydrates, create ATP, store water, or detoxify drugs and poisons.

Explanation

Lysosomes are membranous sacs filled with hydrolytic enzymes that can break down macromolecules. These enzymes can hydrolyze proteins, fats, polysaccharides, and nucleic acids. Lysosomes also have the ability to fuse with other vesicles and organelles in order to digest their contents. Additionally, lysosomes are involved in the transport of budded off vesicles to the Golgi Apparatus. Lysosomes do not metabolize carbohydrates, create ATP, store water, or detoxify drugs and poisons.

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115. Plasma membranes have a trait that allows them to control movement of molecules into and out of the cell, which is called.... _____.

-maintaining internal environment
-regulates homeostasis

Explanation

-maintaining internal environment
-regulates homeostasis

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116. Which elements are the most common in the human body?

Carbon

Calcium

Potassium

Nitrogen

Oxygen

Hydrogen

Phosphorus

The elements carbon, nitrogen, oxygen, and hydrogen are the most common in the human body. These elements are essential for life and are found in various molecules such as proteins, carbohydrates, nucleic acids, and lipids. Carbon is the backbone of organic molecules, while nitrogen is a component of proteins and nucleic acids. Oxygen is necessary for cellular respiration, and hydrogen is involved in various biochemical reactions. These elements play crucial roles in maintaining the structure and function of cells and are abundant in the human body.

Explanation

The elements carbon, nitrogen, oxygen, and hydrogen are the most common in the human body. These elements are essential for life and are found in various molecules such as proteins, carbohydrates, nucleic acids, and lipids. Carbon is the backbone of organic molecules, while nitrogen is a component of proteins and nucleic acids. Oxygen is necessary for cellular respiration, and hydrogen is involved in various biochemical reactions. These elements play crucial roles in maintaining the structure and function of cells and are abundant in the human body.

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117. What do all cells have? (prokaryotic and eukaryotic)

Plasma membrane

Cytosol

Chromosomes

Ribosomes

Endoplasmic reticulum

Nucleus

All cells, both prokaryotic and eukaryotic, have a plasma membrane, which is a selectively permeable barrier that separates the cell from its environment. Cytosol refers to the fluid portion of the cell where various cellular processes occur. Chromosomes are the structures that carry genetic information and are present in all cells. Ribosomes are responsible for protein synthesis and are found in all cells. However, endoplasmic reticulum and nucleus are not present in prokaryotic cells, so they are not correct for the question.

Explanation

All cells, both prokaryotic and eukaryotic, have a plasma membrane, which is a selectively permeable barrier that separates the cell from its environment. Cytosol refers to the fluid portion of the cell where various cellular processes occur. Chromosomes are the structures that carry genetic information and are present in all cells. Ribosomes are responsible for protein synthesis and are found in all cells. However, endoplasmic reticulum and nucleus are not present in prokaryotic cells, so they are not correct for the question.

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118. Why does ice float in liquid water?

Ice always has air bubbles that keep it afloat.

Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquidwater.

The crystalline lattice of ice causes it to be denser than liquid water.

The high surface tension of liquid water keeps the ice on top.

The ionic bonds between the molecules in ice prevent the ice from sinking.

Ice floats in liquid water because of hydrogen bonds. These bonds stabilize and keep the molecules of ice farther apart compared to the water molecules in liquid water. This leads to a decrease in the density of ice, causing it to float on top of the liquid water.

Explanation

Ice floats in liquid water because of hydrogen bonds. These bonds stabilize and keep the molecules of ice farther apart compared to the water molecules in liquid water. This leads to a decrease in the density of ice, causing it to float on top of the liquid water.

119. Characteristics of unsaturated fats...

Forms oils at room temperaature

Can form double bonds which create kinks

Can form single bonds only

Solidifies at room temperature

Has maxed out hydrogen bonded to carbon

Unsaturated fats have the characteristic of forming oils at room temperature because they contain double bonds between carbon atoms in their fatty acid chains. These double bonds create kinks in the chains, preventing them from packing tightly together and forming a solid structure. This is in contrast to saturated fats, which have single bonds between carbon atoms and are solid at room temperature. Unsaturated fats can form double bonds, allowing for flexibility and the ability to remain liquid or semi-solid at room temperature.

Explanation

Unsaturated fats have the characteristic of forming oils at room temperature because they contain double bonds between carbon atoms in their fatty acid chains. These double bonds create kinks in the chains, preventing them from packing tightly together and forming a solid structure. This is in contrast to saturated fats, which have single bonds between carbon atoms and are solid at room temperature. Unsaturated fats can form double bonds, allowing for flexibility and the ability to remain liquid or semi-solid at room temperature.

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120. Artificially saturating the carbons is what kind of fat?

The correct answer is trans, trans fat. Trans fat is a type of fat that is artificially saturated, meaning that hydrogen atoms are added to unsaturated fats to make them solid at room temperature. This process is called hydrogenation and it creates trans fats, which are known to be unhealthy and increase the risk of heart disease. Therefore, artificially saturating the carbons results in trans fats.

Explanation

The correct answer is trans, trans fat. Trans fat is a type of fat that is artificially saturated, meaning that hydrogen atoms are added to unsaturated fats to make them solid at room temperature. This process is called hydrogenation and it creates trans fats, which are known to be unhealthy and increase the risk of heart disease. Therefore, artificially saturating the carbons results in trans fats.

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121. Comparing CO2 and methane (CH4), the shared electrons in the covalent bonds are

Closer to oxygen in CO2

Closer to carbon in CO2

Closer to hydrogen in CH4

Closer to carbon in CH4

because oxygen is more electronegative

Explanation

because oxygen is more electronegative

122. There are 20 different amino acids. What makes one amino acid different from another?

The r group attached to a carboxyl carbon

The r group attached to an amino acid group

The r group attached to an a carbon

Different structural and optical isomers

The R group attached to an alpha carbon is what makes one amino acid different from another. The alpha carbon is a central carbon atom in the amino acid molecule, and the R group is a variable side chain that differs between amino acids. This R group can be a simple hydrogen atom or a complex structure, and it determines the unique properties and functions of each amino acid.

Explanation

The R group attached to an alpha carbon is what makes one amino acid different from another. The alpha carbon is a central carbon atom in the amino acid molecule, and the R group is a variable side chain that differs between amino acids. This R group can be a simple hydrogen atom or a complex structure, and it determines the unique properties and functions of each amino acid.

123. Which is true about water?

It is polar.

It has a cohesive property.

It is a versatile solvent

It has a high specific heat

It expands upon freezing

Water is polar because it has a positive charge on one end and a negative charge on the other due to its bent molecular structure. This polarity allows water molecules to attract each other, giving it a cohesive property. Water is also known as a versatile solvent because it can dissolve many different substances due to its polar nature. Additionally, water has a high specific heat, meaning it can absorb and retain a large amount of heat without a significant change in temperature. Lastly, water expands upon freezing, which is why ice floats on water.

Explanation

Water is polar because it has a positive charge on one end and a negative charge on the other due to its bent molecular structure. This polarity allows water molecules to attract each other, giving it a cohesive property. Water is also known as a versatile solvent because it can dissolve many different substances due to its polar nature. Additionally, water has a high specific heat, meaning it can absorb and retain a large amount of heat without a significant change in temperature. Lastly, water expands upon freezing, which is why ice floats on water.

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124. Which of the following are nitrogenous bases of the pyrimidine type? (one ring)

Cytosine

Thymine

Uracil

Adenine

Guanine

Cytosine, thymine, and uracil are nitrogenous bases of the pyrimidine type because they have a single ring structure. Adenine and guanine, on the other hand, are purine bases, which have a double-ring structure.

Explanation

Cytosine, thymine, and uracil are nitrogenous bases of the pyrimidine type because they have a single ring structure. Adenine and guanine, on the other hand, are purine bases, which have a double-ring structure.

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125. What is this an image of?

α helix secondary structure of a polypeptide.

β pleated sheet secondary structure of a polypeptide.

Double-helical structure of a DNA molecule

1-4 linkage of the β glucose monomers of cellulose.

1-4 linkage of the α glucose monomers of starch.

This image is showing the α helix secondary structure of a polypeptide. The α helix is a common folding pattern in proteins where the polypeptide chain forms a right-handed helical structure stabilized by hydrogen bonds between the amino acids. This structure allows the protein to have a compact and stable conformation.

Explanation

This image is showing the α helix secondary structure of a polypeptide. The α helix is a common folding pattern in proteins where the polypeptide chain forms a right-handed helical structure stabilized by hydrogen bonds between the amino acids. This structure allows the protein to have a compact and stable conformation.

126. Phosphorous has an atomic number of 15, in the first shell it has _____ electrons, second shell has _____ electrons, and third shell has _____ electrons.

Phosphorous has an atomic number of 15, which means it has 15 protons and 15 electrons. The electrons are distributed in different shells around the nucleus. The first shell can hold a maximum of 2 electrons, so it has 2 electrons. The second shell can hold a maximum of 8 electrons, so it has 8 electrons. The remaining 5 electrons are in the third shell. Therefore, the correct answer is 2, two, 8, eight, 5, five.

Explanation

Phosphorous has an atomic number of 15, which means it has 15 protons and 15 electrons. The electrons are distributed in different shells around the nucleus. The first shell can hold a maximum of 2 electrons, so it has 2 electrons. The second shell can hold a maximum of 8 electrons, so it has 8 electrons. The remaining 5 electrons are in the third shell. Therefore, the correct answer is 2, two, 8, eight, 5, five.

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127. Organelles of the endomembrane system: (structure)

Membranous sac of hydrolytic enzymes (in animal cells)

Has cis and trans; stacks of flattened membranous sacs

Large membrane-bounded vesicle

Extensive network of membrane-bounded tubules and sacs, membrane separates lumen from cytosol

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128. Match the following:

2 or more different elements combined in fixed ratio

molecule attraction to other molecules

attraction of molecules/compounds to itself

atoms covalently bonded together

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129. A triglyceride

Consists of three fatty acids attached to a glycerol.

Hydrophobic

Plays a role in energy storage.

Is soluble in water

A triglyceride consists of three fatty acids attached to a glycerol. This means that there are three fatty acid molecules bonded to a glycerol molecule. Triglycerides are hydrophobic, meaning they do not dissolve in water. This is because the fatty acid chains are nonpolar and repel water molecules. Triglycerides also play a role in energy storage. They are a major form of stored energy in the body and can be broken down to release energy when needed.

Explanation

A triglyceride consists of three fatty acids attached to a glycerol. This means that there are three fatty acid molecules bonded to a glycerol molecule. Triglycerides are hydrophobic, meaning they do not dissolve in water. This is because the fatty acid chains are nonpolar and repel water molecules. Triglycerides also play a role in energy storage. They are a major form of stored energy in the body and can be broken down to release energy when needed.

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130. How will brief heating (to 95°C) affect macromolecular structures in aqueous solution?

Proteins will hydrolyze into amino acids.

Proteins will unfold (denature).

Starch will hydrolyze into monomeric sugars.

DNA duplexes will unwind and separate.

Brief heating to 95°C will cause proteins to unfold and denature. This is because heat disrupts the weak interactions, such as hydrogen bonds and hydrophobic interactions, that maintain the protein's folded structure. Denaturation leads to the loss of the protein's functional shape and can result in the loss of its biological activity. On the other hand, DNA duplexes will unwind and separate under brief heating. The heat disrupts the hydrogen bonds between the complementary base pairs, causing the double-stranded DNA to separate into single strands. This process is known as DNA melting or denaturation.

Explanation

Brief heating to 95°C will cause proteins to unfold and denature. This is because heat disrupts the weak interactions, such as hydrogen bonds and hydrophobic interactions, that maintain the protein's folded structure. Denaturation leads to the loss of the protein's functional shape and can result in the loss of its biological activity. On the other hand, DNA duplexes will unwind and separate under brief heating. The heat disrupts the hydrogen bonds between the complementary base pairs, causing the double-stranded DNA to separate into single strands. This process is known as DNA melting or denaturation.

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131. Match the order of the secretory pathway:

3

2

5

4

1

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132. Central dogma processes, match the following:

DNA -> mRNA

mRNA -> Protein

Transcription done by

Translation done by

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133. Functions of the organelles of endomembrane system:

Synthesis of lipids, metabolism of carbohydrates, calcium ion storage, and detoxification of poison and drugs

Digestion, storage, waste disposal, water balance, plant cell growth, and protection

Modification of proteins, carbohydrates on proteins, and phospholipids, secretes packages in vesicles

Breakdown of ingested substances, cell macromolecules, and damaged organelles for recycling.

Aids in synthesis of secretory and other proteins from bound ribosomes; adds carbohydrates to proteins to make glycoproteins; produces new membrane

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134. Which one do you like?

It is a saturated fatty acid.

A diet rich in this molecule may contribute to atherosclerosis.

Molecules of this type are usually liquid at room temperature.

All above

It is a saturated fatty acid and a diet rich in this molecule may contribute to atherosclerosis.

The correct answer is "Molecules of this type are usually liquid at room temperature." This is because the previous statements mention that it is a saturated fatty acid and a diet rich in this molecule may contribute to atherosclerosis, but they do not indicate anything about the physical state of the molecule. However, the statement that molecules of this type are usually liquid at room temperature provides new information and completes the explanation.

Explanation

The correct answer is "Molecules of this type are usually liquid at room temperature." This is because the previous statements mention that it is a saturated fatty acid and a diet rich in this molecule may contribute to atherosclerosis, but they do not indicate anything about the physical state of the molecule. However, the statement that molecules of this type are usually liquid at room temperature provides new information and completes the explanation.

135. Molecules with which functional groups may form polymers via dehydration reactions?

Carboxyl

Hydroxyl

Amino

R group

Carboxyl and hydroxyl functional groups may form polymers via dehydration reactions. In a dehydration reaction, a water molecule is removed to form a covalent bond between two monomers. Carboxyl groups (-COOH) contain both a carbonyl group and a hydroxyl group, allowing them to participate in polymerization reactions. Hydroxyl groups (-OH) also have the necessary hydroxyl group to react with other monomers. Amino groups (-NH2) and R groups (representing any side chain) are not typically involved in dehydration polymerization reactions.

Explanation

Carboxyl and hydroxyl functional groups may form polymers via dehydration reactions. In a dehydration reaction, a water molecule is removed to form a covalent bond between two monomers. Carboxyl groups (-COOH) contain both a carbonyl group and a hydroxyl group, allowing them to participate in polymerization reactions. Hydroxyl groups (-OH) also have the necessary hydroxyl group to react with other monomers. Amino groups (-NH2) and R groups (representing any side chain) are not typically involved in dehydration polymerization reactions.

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136. The molecular formula for glucose is C₆H₁₂O₆. What would be the molecular formula for a polymer made by linking ten glucose molecules together by dehydration reactions?

C₆₀H₁₂₀O₆₀

C₆H₁₂O₆

C₆₀H₁₀₂O₅₁

C₆₀H₁₀₀O₅₀

C₆₀H₁₁₁O₅₁

When ten glucose molecules are linked together by dehydration reactions, water molecules are removed, resulting in the formation of a polymer. Since each glucose molecule has the molecular formula C₆H₁₂O₆, the total number of carbon atoms in the polymer would be 6 multiplied by 10, which is 60. Similarly, the total number of hydrogen atoms would be 12 multiplied by 10, which is 120, and the total number of oxygen atoms would be 6 multiplied by 10, which is 60. Therefore, the molecular formula for the polymer would be C₆₀H₁₀₂O₅₁.

Explanation

When ten glucose molecules are linked together by dehydration reactions, water molecules are removed, resulting in the formation of a polymer. Since each glucose molecule has the molecular formula C₆H₁₂O₆, the total number of carbon atoms in the polymer would be 6 multiplied by 10, which is 60. Similarly, the total number of hydrogen atoms would be 12 multiplied by 10, which is 120, and the total number of oxygen atoms would be 6 multiplied by 10, which is 60. Therefore, the molecular formula for the polymer would be C₆₀H₁₀₂O₅₁.

137. Structure and Function of Nucleus:

Surrounded by nuclear envelope (double membrane)

Houses chromosomes (made of chromatin), DNA, protein

Two subunits made of ribosomal RNA and proteins; can be free in cytoplasm or bound to ER

Protein synthesis

Has nucleoli (where ribosomes are made)

Pores regulate entry & exit of materials

Nuclear envelope continuous with endoplasmic reticulum

The correct answer includes several key points about the structure and function of the nucleus. It mentions that the nucleus is surrounded by a double membrane called the nuclear envelope and that it houses chromosomes made of chromatin, as well as DNA and protein. It also notes that the nucleus has nucleoli, which are responsible for making ribosomes. Additionally, it states that the pores in the nuclear envelope regulate the entry and exit of materials, and that the nuclear envelope is continuous with the endoplasmic reticulum.

Explanation

The correct answer includes several key points about the structure and function of the nucleus. It mentions that the nucleus is surrounded by a double membrane called the nuclear envelope and that it houses chromosomes made of chromatin, as well as DNA and protein. It also notes that the nucleus has nucleoli, which are responsible for making ribosomes. Additionally, it states that the pores in the nuclear envelope regulate the entry and exit of materials, and that the nuclear envelope is continuous with the endoplasmic reticulum.

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138. Eukaryotes have...

Large numbers of organelles; many different types

Extensive cytoskeletons, usually found throughout volume of cell

Limited cytoskeletons

Extensive internal membranes only in photosynthetic species; limited types and numbers of organelles

Larger in size

Smaller in size

Internal Membranes and Organelles:
Prokaryotes → extensive internal membranes only in photosynthetic species; limited types and numbers of organelles
Eukaryotes → large numbers of organelles; many different types
Cytoskeleton:
Helps move around individual proteins, enzymes, vesicles, etc
Prokaryotes → limited in extent, relative to eukaryotes
Eukaryotes → extensive, usually found throughout volume of cell
Overall Size:
Prokaryotes → usually small compared to eukaryotes
Eukaryotes → most are larger than prokaryotes

Explanation

Internal Membranes and Organelles:
Prokaryotes → extensive internal membranes only in photosynthetic species; limited types and numbers of organelles
Eukaryotes → large numbers of organelles; many different types
Cytoskeleton:
Helps move around individual proteins, enzymes, vesicles, etc
Prokaryotes → limited in extent, relative to eukaryotes
Eukaryotes → extensive, usually found throughout volume of cell
Overall Size:
Prokaryotes → usually small compared to eukaryotes
Eukaryotes → most are larger than prokaryotes

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139. In DNA, the backbone is connected by _____ bonds, but the bases are held by _____ bonds.

The backbone of DNA is made up of sugar-phosphate molecules that are connected by covalent bonds. These bonds are strong and stable, providing structural support to the DNA molecule. On the other hand, the bases of DNA (adenine, thymine, cytosine, and guanine) are held together by hydrogen bonds. These bonds are relatively weak, allowing the DNA strands to separate during processes such as replication and transcription.

Explanation

The backbone of DNA is made up of sugar-phosphate molecules that are connected by covalent bonds. These bonds are strong and stable, providing structural support to the DNA molecule. On the other hand, the bases of DNA (adenine, thymine, cytosine, and guanine) are held together by hydrogen bonds. These bonds are relatively weak, allowing the DNA strands to separate during processes such as replication and transcription.

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140. Protein vesicles from rough ER enter at the _____ face of Golgi and exit at the _____ face of the Golgi Body.

Protein vesicles from the rough ER enter at the cis face of the Golgi and exit at the trans face of the Golgi Body. The cis face is the receiving side of the Golgi, where vesicles fuse and deliver their cargo. The trans face is the shipping side of the Golgi, where vesicles bud off and transport proteins to their final destinations.

Explanation

Protein vesicles from the rough ER enter at the cis face of the Golgi and exit at the trans face of the Golgi Body. The cis face is the receiving side of the Golgi, where vesicles fuse and deliver their cargo. The trans face is the shipping side of the Golgi, where vesicles bud off and transport proteins to their final destinations.

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141. Function and structure of ribosomes

Protein synthesis

Surrounded by nuclear envelope (double membrane)

Houses chromosomes (made of chromatin), DNA, protein,& nucleoli

Has pores that regulate entry & exit of materials

Two subunits made of ribosomal RNA and proteins

Can be free or bound

Can be found on rough ER and nuclear envelope

Ribosomes are responsible for protein synthesis. They consist of two subunits made of ribosomal RNA and proteins. Ribosomes can be either free in the cytoplasm or bound to the rough endoplasmic reticulum (ER) and the nuclear envelope. The ribosomes on the rough ER are involved in the synthesis of proteins that will be transported out of the cell, while the free ribosomes synthesize proteins that will function within the cytoplasm. This structure and function of ribosomes allow them to play a crucial role in the production of proteins in the cell.

Explanation

Ribosomes are responsible for protein synthesis. They consist of two subunits made of ribosomal RNA and proteins. Ribosomes can be either free in the cytoplasm or bound to the rough endoplasmic reticulum (ER) and the nuclear envelope. The ribosomes on the rough ER are involved in the synthesis of proteins that will be transported out of the cell, while the free ribosomes synthesize proteins that will function within the cytoplasm. This structure and function of ribosomes allow them to play a crucial role in the production of proteins in the cell.

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142. Which are following functions of proteins?

Defense

Structure

Transportation

Communication

Enzymes

Genetic

Storage

Receptors

Contractile/motor

Homeostasis

Proteins have a variety of functions in the body. They play a crucial role in defense by forming antibodies that help fight against infections and diseases. Proteins also provide structural support to cells and tissues, contributing to the overall structure of the body. They are involved in transportation, aiding in the movement of molecules and substances across cell membranes. Communication is another function of proteins, as they act as signaling molecules and help transmit messages within the body. Enzymes, which are specialized proteins, catalyze chemical reactions in the body. Proteins also serve as genetic storage, storing and transmitting genetic information. They act as receptors, allowing cells to respond to various signals. Additionally, proteins are involved in contraction and movement, contributing to the motor function of the body. Lastly, proteins help maintain homeostasis, the balance of internal conditions in the body.

Explanation

Proteins have a variety of functions in the body. They play a crucial role in defense by forming antibodies that help fight against infections and diseases. Proteins also provide structural support to cells and tissues, contributing to the overall structure of the body. They are involved in transportation, aiding in the movement of molecules and substances across cell membranes. Communication is another function of proteins, as they act as signaling molecules and help transmit messages within the body. Enzymes, which are specialized proteins, catalyze chemical reactions in the body. Proteins also serve as genetic storage, storing and transmitting genetic information. They act as receptors, allowing cells to respond to various signals. Additionally, proteins are involved in contraction and movement, contributing to the motor function of the body. Lastly, proteins help maintain homeostasis, the balance of internal conditions in the body.

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143. Fats are made out of _____ and _____.

The correct answer is glycerol and fatty acids. Glycerol and fatty acids are the two components that make up fats. Glycerol is a type of alcohol that combines with fatty acids to form triglycerides, which are the main type of fat found in our bodies and in food. Fatty acids are long chains of carbon atoms with a carboxyl group at one end, and they can be saturated or unsaturated depending on the presence of double bonds. Together, glycerol and fatty acids create the structure and function of fats in our bodies.

Explanation

The correct answer is glycerol and fatty acids. Glycerol and fatty acids are the two components that make up fats. Glycerol is a type of alcohol that combines with fatty acids to form triglycerides, which are the main type of fat found in our bodies and in food. Fatty acids are long chains of carbon atoms with a carboxyl group at one end, and they can be saturated or unsaturated depending on the presence of double bonds. Together, glycerol and fatty acids create the structure and function of fats in our bodies.

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144. The phospholipids that make up the plasma membrane have _____ heads and _____ tails.

Phospholipids are composed of a hydrophilic head and hydrophobic tails. The hydrophilic head is attracted to water molecules and is polar, while the hydrophobic tails repel water and are nonpolar. This arrangement results in the formation of a phospholipid bilayer, with the hydrophilic heads facing the aqueous environment on both sides and the hydrophobic tails forming a barrier in the middle. This structure allows the plasma membrane to regulate the passage of substances in and out of the cell.

Explanation

Phospholipids are composed of a hydrophilic head and hydrophobic tails. The hydrophilic head is attracted to water molecules and is polar, while the hydrophobic tails repel water and are nonpolar. This arrangement results in the formation of a phospholipid bilayer, with the hydrophilic heads facing the aqueous environment on both sides and the hydrophobic tails forming a barrier in the middle. This structure allows the plasma membrane to regulate the passage of substances in and out of the cell.

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145.

If a DNA sample were composed of 10% thymine, what would be the percentage of guanine?

If a DNA sample is composed of 10% thymine, it means that the remaining 90% must be made up of the other three nucleotides: adenine, cytosine, and guanine. Since DNA is a double-stranded molecule, the percentage of guanine would be the same as the percentage of cytosine. Therefore, if thymine accounts for 10% of the DNA, guanine and cytosine together would account for the remaining 90%. Dividing this 90% in half gives us 45%, which means that guanine would also be 45% of the DNA.

Explanation

If a DNA sample is composed of 10% thymine, it means that the remaining 90% must be made up of the other three nucleotides: adenine, cytosine, and guanine. Since DNA is a double-stranded molecule, the percentage of guanine would be the same as the percentage of cytosine. Therefore, if thymine accounts for 10% of the DNA, guanine and cytosine together would account for the remaining 90%. Dividing this 90% in half gives us 45%, which means that guanine would also be 45% of the DNA.

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146. Lipids have three types: _____, _____, and _____. (all plural)

Lipids are organic compounds that are insoluble in water. They have three main types: fats, phospholipids, and steroids. Fats are the most common type of lipids and are used for energy storage. Phospholipids are a major component of cell membranes and help regulate the movement of substances in and out of cells. Steroids are a class of lipids that have a unique structure and are involved in various physiological processes, such as hormone regulation.

Explanation

Lipids are organic compounds that are insoluble in water. They have three main types: fats, phospholipids, and steroids. Fats are the most common type of lipids and are used for energy storage. Phospholipids are a major component of cell membranes and help regulate the movement of substances in and out of cells. Steroids are a class of lipids that have a unique structure and are involved in various physiological processes, such as hormone regulation.

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147. What aspects of protein structure are stabilized or assisted by hydrogen bonds?

Primary

Secondary

Tertiary

Quarternary

All the above

Secondary, tertiary, and quaternary structures, but not primary structure

Hydrogen bonds play a crucial role in stabilizing the secondary, tertiary, and quaternary structures of proteins. In secondary structure, hydrogen bonds form between the carbonyl oxygen of one amino acid and the hydrogen of another amino acid, creating alpha helices and beta sheets. In tertiary structure, hydrogen bonds contribute to the folding and stabilization of the overall 3D structure of the protein. In quaternary structure, hydrogen bonds are involved in the interactions between multiple protein subunits, helping to hold them together. However, hydrogen bonds do not directly stabilize the primary structure of proteins, which refers to the linear sequence of amino acids.

Explanation

Hydrogen bonds play a crucial role in stabilizing the secondary, tertiary, and quaternary structures of proteins. In secondary structure, hydrogen bonds form between the carbonyl oxygen of one amino acid and the hydrogen of another amino acid, creating alpha helices and beta sheets. In tertiary structure, hydrogen bonds contribute to the folding and stabilization of the overall 3D structure of the protein. In quaternary structure, hydrogen bonds are involved in the interactions between multiple protein subunits, helping to hold them together. However, hydrogen bonds do not directly stabilize the primary structure of proteins, which refers to the linear sequence of amino acids.

148. Which modifications of fatty acids will best keep triglycerides solid at warmer temperatures?

Creating cis double bonds to the fatty acids

Adding hydrogens to the fatty acids

Creating trans double bonds to the fatty acids

Adding hydrogens and trans double bonds to the fatty acids

Adding cis double bonds and trans double bonds to the fatty acids

Adding hydrogens and trans double bonds to the fatty acids will best keep triglycerides solid at warmer temperatures. Trans double bonds introduce rigidity into the fatty acid chain, making it more difficult for the triglycerides to melt and remain solid at higher temperatures. Additionally, adding hydrogens to the fatty acids increases the saturation level, which also contributes to the solidification of triglycerides.

Explanation

Adding hydrogens and trans double bonds to the fatty acids will best keep triglycerides solid at warmer temperatures. Trans double bonds introduce rigidity into the fatty acid chain, making it more difficult for the triglycerides to melt and remain solid at higher temperatures. Additionally, adding hydrogens to the fatty acids increases the saturation level, which also contributes to the solidification of triglycerides.

149. 3 components of a nucleotide..._____, _____, and _____?

The correct answer is sugar, deoxyribose sugar, deoxyribose, pentose sugar, phosphate group, phosphate, nitrogenous base, base. A nucleotide is composed of three main components: a sugar (either deoxyribose or ribose), a phosphate group, and a nitrogenous base. The sugar component can be either deoxyribose or ribose, both of which are types of pentose sugars. The phosphate group is responsible for linking the nucleotides together to form a DNA or RNA strand. The nitrogenous base can be one of four options: adenine (A), thymine (T), cytosine (C), or guanine (G). These components together make up the structure of a nucleotide.

Explanation

The correct answer is sugar, deoxyribose sugar, deoxyribose, pentose sugar, phosphate group, phosphate, nitrogenous base, base. A nucleotide is composed of three main components: a sugar (either deoxyribose or ribose), a phosphate group, and a nitrogenous base. The sugar component can be either deoxyribose or ribose, both of which are types of pentose sugars. The phosphate group is responsible for linking the nucleotides together to form a DNA or RNA strand. The nitrogenous base can be one of four options: adenine (A), thymine (T), cytosine (C), or guanine (G). These components together make up the structure of a nucleotide.

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151. Which is the correct sequence of increasing organization? (start from beginning)_____, _____, _____, _____, _____, [Blank], _____, _____, _____ and _____.

The correct sequence of increasing organization starts with atoms, followed by molecules, macromolecules, organelles, cells, tissues, organs, organ systems, and finally organisms. This sequence represents a hierarchical organization where smaller units combine to form larger and more complex structures. Atoms are the basic building blocks of matter, which combine to form molecules. Molecules then combine to form macromolecules, such as proteins and nucleic acids. Organelles are specialized structures within cells, which are the basic units of life. Cells then combine to form tissues, which further organize into organs. Organs work together to form organ systems, and all the organ systems together make up an organism.

Explanation

The correct sequence of increasing organization starts with atoms, followed by molecules, macromolecules, organelles, cells, tissues, organs, organ systems, and finally organisms. This sequence represents a hierarchical organization where smaller units combine to form larger and more complex structures. Atoms are the basic building blocks of matter, which combine to form molecules. Molecules then combine to form macromolecules, such as proteins and nucleic acids. Organelles are specialized structures within cells, which are the basic units of life. Cells then combine to form tissues, which further organize into organs. Organs work together to form organ systems, and all the organ systems together make up an organism.

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152. Which two functional groups are always found in amino acids? _____ and _____?

Amino acids always contain two functional groups: the amino group (NH2) and the carboxyl group (COOH). These groups are essential for the formation of peptide bonds and the overall structure and function of proteins.

Explanation

Amino acids always contain two functional groups: the amino group (NH2) and the carboxyl group (COOH). These groups are essential for the formation of peptide bonds and the overall structure and function of proteins.

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153. You isolate a molecule and determine it is nonpolar. Based on this property, the molecule is largely composed of the elements _____ and _____.

The correct answer is carbon, hydrogen. This is because carbon and hydrogen are both nonpolar elements. Nonpolar molecules are composed of atoms that have similar electronegativities, meaning they share electrons equally and do not have a significant charge imbalance. Carbon and hydrogen have similar electronegativities, making them suitable for forming nonpolar molecules.

Explanation

The correct answer is carbon, hydrogen. This is because carbon and hydrogen are both nonpolar elements. Nonpolar molecules are composed of atoms that have similar electronegativities, meaning they share electrons equally and do not have a significant charge imbalance. Carbon and hydrogen have similar electronegativities, making them suitable for forming nonpolar molecules.

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154. Types of ribosomes:

Free ribosome (location)

Bound ribosome (location)

Free ribosome (function)

Bound ribosome (function)

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155. What is a hypothesis?

A hypothesis is a testable answer to a question. It is a proposed explanation or prediction that can be tested through experimentation or observation. By formulating a hypothesis, researchers can make predictions and design experiments to gather evidence and support their proposed answer. A hypothesis should be specific, measurable, and falsifiable, meaning that it can be proven wrong if the evidence does not support it.

Explanation

A hypothesis is a testable answer to a question. It is a proposed explanation or prediction that can be tested through experimentation or observation. By formulating a hypothesis, researchers can make predictions and design experiments to gather evidence and support their proposed answer. A hypothesis should be specific, measurable, and falsifiable, meaning that it can be proven wrong if the evidence does not support it.

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156. Match the following proteins to it's function:

Ferritin

Calcium Pump

Collagen

White Blood Cells

Hormones

Polymerase

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157. Match the following:

Carbon

Nitrogen

Hydrogen

Oxygen

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158. Where are phospholipids most likely to be found?

Phospholipids are a type of lipid molecule that have a hydrophilic (water-loving) head and hydrophobic (water-fearing) tails. Due to this structure, they are most likely to be found in the phospholipid bilayer of the cell membrane. The phospholipid bilayer forms a barrier between the cell's internal environment and the external environment, allowing for selective permeability and regulation of what enters and exits the cell. Therefore, it is the most suitable location for phospholipids to be found.

Explanation

Phospholipids are a type of lipid molecule that have a hydrophilic (water-loving) head and hydrophobic (water-fearing) tails. Due to this structure, they are most likely to be found in the phospholipid bilayer of the cell membrane. The phospholipid bilayer forms a barrier between the cell's internal environment and the external environment, allowing for selective permeability and regulation of what enters and exits the cell. Therefore, it is the most suitable location for phospholipids to be found.

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