1.
Which of the following is a polymer of amino acids?
Correct Answer
A. Protein
Explanation
Proteins are polymers of amino acids, consisting of long chains of amino acids linked together by peptide bonds. They are essential macromolecules that play a crucial role in various biological processes, such as enzyme catalysis, cell signaling, and structural support. Carbohydrates, lipids, and nucleic acids are also important biomolecules, but they are not polymers of amino acids.
2.
Which of the following is a polymer of nucleotides?
Correct Answer
A. Nucleic Acid
Explanation
Nucleic acids are polymers of nucleotides. Nucleotides are the building blocks of nucleic acids, which include DNA and RNA. They consist of a sugar molecule, a phosphate group, and a nitrogenous base. These nucleotides join together through phosphodiester bonds to form a long chain, resulting in the formation of nucleic acids. Therefore, nucleic acid is the correct answer as it is the only option that represents a polymer of nucleotides.
3.
Which of the following monomers make up a lipid?
Correct Answer
A. Glycerol and fatty acid
Explanation
Lipids are composed of glycerol and fatty acids. Glycerol is a three-carbon alcohol molecule, while fatty acids are long hydrocarbon chains with a carboxyl group at one end. These two monomers combine through dehydration synthesis to form a lipid molecule, with the fatty acids attaching to the glycerol backbone. Therefore, the correct answer is glycerol and fatty acid.
4.
Which of the following is NOT a nucleotide found in DNA?
Correct Answer
C. Uracil
Explanation
Uracil is not a nucleotide found in DNA. DNA is composed of four nucleotides: adenine, cytosine, guanine, and thymine. Uracil is found in RNA instead of DNA. It replaces thymine in RNA and pairs with adenine during transcription.
5.
Which of the following is a structural form of carbohydrate?
Correct Answer
A. Cellulose
Explanation
Cellulose is a structural form of carbohydrate because it is a complex polysaccharide made up of glucose molecules linked together. It forms the main structural component of plant cell walls and provides rigidity and strength to the plant. Starch, on the other hand, is a storage form of carbohydrate, enzymes are proteins that catalyze chemical reactions, and RNA is a nucleic acid involved in protein synthesis.
6.
The functional group -NH2 is called the ____.
Correct Answer
A. Amino group
Explanation
The functional group -NH2 is called the amino group. It consists of a nitrogen atom bonded to two hydrogen atoms. Amino groups are commonly found in organic compounds such as amino acids, which are the building blocks of proteins. This group is responsible for the basic properties of amino acids and plays a crucial role in the formation of peptide bonds.
7.
How many amino acids are found in humans?
Correct Answer
C. 20
Explanation
There are 20 amino acids found in humans. Amino acids are the building blocks of proteins and are essential for various biological processes in the body. They play a crucial role in the structure and function of cells, tissues, and organs. These amino acids are obtained through the diet or synthesized within the body. Each amino acid has a specific role and contributes to the overall health and functioning of the human body.
8.
When a fat molecule is called "saturated", what is it saturated with?
Correct Answer
D. Hydrogen atoms
Explanation
When a fat molecule is called "saturated", it means that it is saturated with hydrogen atoms. In a saturated fat molecule, each carbon atom is bonded to as many hydrogen atoms as possible, resulting in a straight and rigid structure. This lack of double bonds between carbon atoms allows the fat molecule to be solid at room temperature. In contrast, unsaturated fats have double bonds between some carbon atoms, which introduces kinks in the molecule and makes it liquid at room temperature. Therefore, the correct answer is hydrogen atoms.
9.
Organic compounds always contain the element ____.
Correct Answer
A. Carbon
Explanation
Organic compounds are defined as compounds that contain carbon atoms bonded to other carbon atoms and other elements such as hydrogen, oxygen, nitrogen, sulfur, and more. Carbon is the essential element in organic compounds and is the backbone of their structure. Therefore, it is correct to say that organic compounds always contain the element carbon.
10.
The bonds between amino acids in a protein are called ____.
Correct Answer
C. Peptide bonds
Explanation
Peptide bonds are the correct answer because they are the specific type of chemical bond that connects amino acids together in a protein. These bonds form through a dehydration synthesis reaction, where the carboxyl group of one amino acid reacts with the amino group of another amino acid, resulting in the formation of a peptide bond and the release of a water molecule. Peptide bonds are crucial for protein structure and function, as they determine the sequence and arrangement of amino acids in a protein chain.
11.
Which of the following is NOT true of water?
Correct Answer
C. It can diffuse through lipids easily.
Explanation
Water cannot diffuse through lipids easily because lipids are nonpolar molecules, while water is a polar molecule. Polar molecules are attracted to other polar molecules and repelled by nonpolar molecules. Therefore, water molecules cannot easily pass through the nonpolar lipid bilayer of cell membranes.
12.
Bases are substances with a pH greater than 7.
Correct Answer
A. True
Explanation
Bases are substances that have a pH greater than 7. This means that they have a higher concentration of hydroxide ions (OH-) compared to hydrogen ions (H+). When dissolved in water, bases can accept protons (H+) and decrease the concentration of H+ ions, resulting in a higher pH value. Therefore, the statement that bases have a pH greater than 7 is true.
13.
Most plants use lipids for long-term storage of energy.
Correct Answer
B. False
Explanation
Lipids are not the primary storage form of energy in plants. Instead, plants primarily store energy in the form of carbohydrates, such as starch. Lipids may be used for energy storage in some seeds and fruits, but they are not the main source of long-term energy storage in most plants. Therefore, the statement is false.
14.
Most plants use carbohydrate to build cell walls.
Correct Answer
A. True
Explanation
Plants use carbohydrates, such as cellulose, to build their cell walls. Cell walls provide structural support and protection to plant cells. Carbohydrates are essential for the synthesis of cellulose, which is the main component of plant cell walls. Therefore, it is true that most plants use carbohydrates to build their cell walls.
15.
There are literally hundreds of thousands of different organic molecules. Which statement best explains how this is possible?
Correct Answer
B. Carbon is unique in that it can make four chemical bonds.
Explanation
Carbon is unique in that it can make four chemical bonds. This allows it to form a wide variety of organic molecules with different arrangements and combinations of other elements. Unlike many other elements, carbon has the ability to bond with multiple atoms simultaneously, resulting in a vast number of possible organic compounds. This versatility of carbon's bonding capacity is the primary reason for the existence of such a large number of different organic molecules.
16.
If we find life elsewhere in the universe it is likely to look exactly like life on Earth because there is a limited number of proteins that can be formed.
Correct Answer
B. False
Explanation
The explanation for the answer "False" is that the statement assumes that life elsewhere in the universe would be similar to life on Earth solely based on the limited number of proteins that can be formed. However, this assumption overlooks the possibility of alternative biochemistries and different building blocks for life that could exist in other environments. Therefore, it is not necessarily true that life elsewhere in the universe would look exactly like life on Earth.
17.
The specific chemical that an enzyme will act on is called a(n) ...
Correct Answer
A. Substrate.
Explanation
An enzyme is a type of protein that acts as a catalyst, speeding up chemical reactions in the body. The specific chemical that an enzyme acts on is called a substrate. Enzymes have a specific shape that allows them to bind to a particular substrate, and once bound, the enzyme helps to convert the substrate into a product. Therefore, the correct answer is substrate.
18.
Which phrase best describes the effect of a catalyst on a chemical reaction?
Correct Answer
C. Decreases the activation energy
Explanation
A catalyst is a substance that speeds up a chemical reaction by lowering the activation energy required for the reaction to occur. By doing so, it provides an alternative pathway for the reaction to proceed, allowing it to happen more easily and quickly. Therefore, the correct answer is "decreases the activation energy."
19.
What type of polymer is an enzyme?
Correct Answer
A. Protein
Explanation
Enzymes are a type of protein. Proteins are large, complex molecules made up of amino acids. Enzymes play a crucial role in biological processes by catalyzing chemical reactions in the body. They act as biological catalysts, speeding up the rate of reactions without being consumed in the process. Enzymes are involved in various metabolic pathways and perform specific functions in the body. Therefore, the correct answer is protein.
20.
Which of the following is not one of the top four elements in the body?
Correct Answer
D. Calcium
Explanation
Calcium is not one of the top four elements in the body because it is not as abundant or essential as carbon, hydrogen, nitrogen. Carbon is a key component of organic molecules, hydrogen is found in water and many biomolecules, and nitrogen is a major component of proteins and nucleic acids. Calcium, on the other hand, is an important mineral for bone health and other physiological processes, but it is not considered one of the top four elements in terms of abundance or essentiality in the body.
21.
The name of a sugar typically ends with the suffix -ose.
Correct Answer
A. True
Explanation
The suffix -ose is commonly used to indicate sugars. Therefore, it is accurate to say that the name of a sugar typically ends with the suffix -ose.
22.
The ___ form of this molecule is found in animals and is ___ at room temperature.
Correct Answer
A. Saturated ... solid
Explanation
The saturated form of this molecule is found in animals and is solid at room temperature. Saturated molecules have single bonds between carbon atoms, which allows for a tightly packed structure and higher melting point, resulting in a solid state at room temperature.
23.
Which phrase best describes atoms?
Correct Answer
A. Smallest basic unit of matter
Explanation
The phrase "smallest basic unit of matter" best describes atoms. Atoms are the fundamental building blocks of matter and cannot be broken down further without losing their chemical properties. They consist of a nucleus, which contains positively charged particles called protons and neutral particles called neutrons, surrounded by negatively charged particles called electrons. Therefore, atoms are considered the smallest indivisible units of matter.
24.
An ion is formed when an atom gains or loses ___.
Correct Answer
A. Electrons
Explanation
An ion is formed when an atom gains or loses electrons. Electrons are negatively charged particles that orbit the nucleus of an atom. When an atom gains or loses electrons, it becomes electrically charged and is called an ion. Gaining electrons results in a negative ion, while losing electrons creates a positive ion. Protons and neutrons are not directly involved in the formation of ions, and photons are particles of light that do not have an electric charge.
25.
Atoms connected by covalent bonds share
Correct Answer
A. Pairs of electrons
Explanation
Covalent bonds occur when atoms share pairs of electrons. In this type of bond, the electrons are shared between the atoms, creating a strong bond. This sharing of electrons allows both atoms to achieve a stable electron configuration, fulfilling the octet rule. Ionic compounds, on the other hand, involve the transfer of electrons from one atom to another. Carbon and oxygen are elements that can form covalent bonds, but they are not the only elements capable of doing so. Hydrogen ions do not share electrons, as they are positively charged ions.
26.
Which molecules store and transmit genetic information?
Correct Answer
C. Nucleic acids
Explanation
Nucleic acids store and transmit genetic information. They are composed of nucleotides, which consist of a sugar molecule, a phosphate group, and a nitrogenous base. DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are the two main types of nucleic acids. DNA carries the genetic instructions for the development, functioning, and reproduction of all living organisms, while RNA plays a crucial role in protein synthesis. Lipids, proteins, and carbohydrates are important biomolecules, but they do not primarily store and transmit genetic information.
27.
Which biological macromolecule contains nitrogen bases?
Correct Answer
A. Nucleic acids
Explanation
Nucleic acids are the biological macromolecules that contain nitrogen bases. These include DNA and RNA, which are composed of nucleotides. Nucleotides consist of a nitrogenous base, a sugar molecule, and a phosphate group. The nitrogenous bases in nucleic acids are adenine (A), thymine (T), cytosine (C), guanine (G) in DNA, and uracil (U) in RNA. These nitrogen bases play a crucial role in the genetic information storage and transmission in living organisms.
28.
Water (H2O) is an example of a molecule whose atoms are held together by which of the following?
Correct Answer
A. Covalent bonds
Explanation
Water (H2O) is an example of a molecule whose atoms are held together by covalent bonds. Covalent bonds occur when atoms share electrons in order to achieve a stable electron configuration. In the case of water, each hydrogen atom shares one of its electrons with the oxygen atom, forming two covalent bonds. This sharing of electrons creates a strong bond between the atoms, holding them together and forming the water molecule.
29.
Water is a polar molecule which has a slightly positive side and a slightly negative side. It would be a good solvent for which of the following substances?
Correct Answer
C. Polar pigments
Explanation
Water is a polar molecule because it has a slightly positive side and a slightly negative side. This polarity allows water to dissolve other polar substances, such as polar pigments. Polar pigments have a positive and negative charge, which can be attracted to the positive and negative ends of the water molecule. Therefore, water would be a good solvent for polar pigments.
30.
Which of the following is NOT a property of water?
Correct Answer
A. Non-polar solvent
Explanation
Water is a polar solvent, meaning it has a slight positive charge on one end and a slight negative charge on the other. This polarity allows water to dissolve other polar substances, making it an excellent solvent. Therefore, the correct answer is non-polar solvent, as water is not capable of dissolving non-polar substances.
31.
A solution with a high concentration of H+ ions....
Correct Answer
C. Is very acidic
Explanation
A solution with a high concentration of H+ ions is very acidic because the concentration of H+ ions determines the acidity of a solution. The more H+ ions present, the stronger the acid. A pH of 7 is considered neutral, so it cannot be the correct answer. Killing all organisms is not directly related to the concentration of H+ ions in a solution. Similarly, a high pH indicates alkalinity, not acidity. Therefore, the correct answer is "is very acidic."
32.
Which category of carbon-based molecules includes sugars and starches?
Correct Answer
A. Carbohydrates
Explanation
Carbohydrates are the category of carbon-based molecules that include sugars and starches. Carbohydrates are organic compounds made up of carbon, hydrogen, and oxygen atoms. They are an essential source of energy for living organisms and play a crucial role in various biological processes. Sugars and starches are both types of carbohydrates. Sugars are simple carbohydrates, while starches are complex carbohydrates. They are commonly found in foods like fruits, vegetables, grains, and dairy products.
33.
DNA and RNA are two types of ___.
Correct Answer
D. Nucleic acids
Explanation
DNA and RNA are two types of nucleic acids. Nucleic acids are large biomolecules that are essential for storing and transmitting genetic information. DNA (deoxyribonucleic acid) is the genetic material found in the nucleus of cells and carries the instructions for the development and functioning of living organisms. RNA (ribonucleic acid) is involved in protein synthesis and plays a crucial role in the transfer of genetic information from DNA to proteins. Both DNA and RNA are composed of nucleotides, which are the building blocks of nucleic acids. Therefore, the correct answer is nucleic acids.
34.
Enzymes are a type of ___.
Correct Answer
B. Protein
Explanation
Enzymes are a type of protein. Proteins are large molecules made up of amino acids, and enzymes are a specific type of protein that act as catalysts in biochemical reactions. They speed up the rate of these reactions by lowering the activation energy required for the reaction to occur. Enzymes are involved in various biological processes and are essential for the proper functioning of cells and organisms.
35.
What is the term for the amount of energy that needs to be added for a chemical reaction to start?
Correct Answer
A. Activation energy
Explanation
Activation energy refers to the amount of energy that needs to be added to a chemical reaction in order for it to start. This energy is required to break the existing bonds in the reactant molecules and initiate the formation of new bonds in the product molecules. Activation energy acts as a barrier that must be overcome for a reaction to occur, and it determines the rate at which the reaction proceeds.
36.
Which phrase best describes an exothermic chemical reaction?
Correct Answer
B. Releases more energy than it absorbs
Explanation
An exothermic chemical reaction is one that releases more energy than it absorbs. This means that during the reaction, energy is being released into the surroundings, resulting in an increase in temperature. In contrast, an endothermic reaction absorbs more energy than it releases, causing a decrease in temperature. Therefore, the phrase "releases more energy than it absorbs" accurately describes an exothermic chemical reaction.
37.
Which phrase best describes the effect of a catalyst on a chemical reaction?
Correct Answer
B. Increases the reaction rate
Explanation
A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. It achieves this by providing an alternative pathway with a lower activation energy for the reaction to occur. This allows more reactant particles to have sufficient energy to overcome the activation energy barrier and form the products. Therefore, the phrase "increases the reaction rate" best describes the effect of a catalyst on a chemical reaction.
38.
Enzymes affect chemical reactions in living organisms by
Correct Answer
A. Weakening bonds in reactants.
Explanation
Enzymes are biological catalysts that speed up chemical reactions in living organisms. They do this by weakening the bonds in reactant molecules, making it easier for the reaction to occur. Enzymes achieve this by binding to the reactant molecules and exerting a force that destabilizes the bonds, lowering the activation energy required for the reaction to proceed. This allows the reaction to happen more quickly and efficiently.
39.
The specific reactants that an enzyme acts on are called ___.
Correct Answer
C. Substrates
Explanation
Enzymes are proteins that act as catalysts in biochemical reactions. They bind to specific molecules called substrates and facilitate the conversion of these substrates into products. Therefore, the correct answer is substrates.
40.
A(n) ___ is a macromolecule made of many smaller molecules bonded together.
Correct Answer
A. Polymer
Explanation
A polymer is a macromolecule made of many smaller molecules bonded together. This is because polymers are formed through a process called polymerization, where monomers (smaller molecules) are chemically bonded together to form long chains or networks. The resulting polymer has unique properties and characteristics based on the type and arrangement of monomers used in its formation.
41.
A(n) ___ is a molecular subunit of a polymer.
Correct Answer
B. Monomer
Explanation
A monomer is a molecular subunit of a polymer. Polymers are large molecules made up of repeating smaller units called monomers. These monomers join together through chemical bonds to form a polymer chain. Therefore, a monomer is an essential building block for the formation of polymers.
42.
A(n) ___ is a substance that dissolves in a solvent.
Correct Answer
A. Solute
Explanation
A solute is a substance that dissolves in a solvent. When a solute is added to a solvent, it disperses evenly throughout the solvent, resulting in a solution. The solute particles become evenly distributed and surrounded by solvent particles, forming a homogeneous mixture. This process is known as dissolution. A solute can be a solid, liquid, or gas, and it can be dissolved in various types of solvents, such as water, alcohol, or oil. The solute-solvent interaction is essential in many chemical and biological processes, including the transportation of nutrients in living organisms and the creation of various solutions in chemistry.
43.
A(n) ___ is a substance in which a solute dissolves and is in greatest concentration in a solution.
Correct Answer
B. Solvent
Explanation
A solvent is a substance in which a solute dissolves and is in greatest concentration in a solution. In a solution, the solute is the substance that is being dissolved, while the solvent is the substance that does the dissolving. The solvent is usually present in a larger amount compared to the solute, which is why it is in the greatest concentration. The solute particles disperse and mix with the solvent particles, creating a homogeneous mixture.
44.
What part is labeled B?
Correct Answer
B. Ribose Sugar
Explanation
The correct answer is Ribose Sugar. Ribose sugar is a component of nucleotides, which are the building blocks of nucleic acids like DNA and RNA. It is a five-carbon sugar that forms the backbone of the nucleic acid molecule. In this question, the part labeled B is referring to the ribose sugar within a nucleotide.
45.
What part is labeled C?
Correct Answer
C. Nitrogen Base
Explanation
The correct answer is Nitrogen Base. Nitrogen bases are one of the three components of a nucleotide, which is the building block of nucleic acids like DNA and RNA. Nitrogen bases include adenine, thymine, guanine, cytosine (in DNA), and uracil (in RNA). They are responsible for the genetic information carried by nucleic acids. In the given question, the part labeled C is referring to the nitrogen base component of the nucleotide.
46.
What part is labeled A?
Correct Answer
A. pHospHate
47.
This is a diagram of a monomer called a ___.
Correct Answer
D. Nucleotide
Explanation
The diagram represents a monomer, which is a single unit that can combine with other units to form a larger molecule. In this case, the monomer is specifically a nucleotide. Nucleotides are the building blocks of nucleic acids, such as DNA and RNA. They consist of three components: a phosphate group, a ribose sugar, and a nitrogen base. The diagram likely shows all three components, indicating that it is a nucleotide.
48.
This is a diagram of a monomer that is used to build ___.
Correct Answer
C. Nucleic Acids
Explanation
The diagram of the monomer suggests that it is a nucleotide, which is the building block of nucleic acids. Nucleic acids, such as DNA and RNA, are composed of long chains of nucleotides that carry genetic information and play important roles in protein synthesis and cellular functions. Therefore, the correct answer is nucleic acids.
49.
The structure labeled A is called ___.
Correct Answer
A. Glycerol
Explanation
The structure labeled A is called glycerol because it matches the chemical structure of glycerol, which is a three-carbon alcohol molecule. Glycerol is a key component of lipids, such as triglycerides, and is commonly found in biological systems. It is not a fatty acid, amino acid, or nucleotide, as those have different chemical structures and functions.
50.
The structures labeled B are ___.
Correct Answer
A. Fatty acids
Explanation
The structures labeled B in the given question are fatty acids. Fatty acids are organic molecules that consist of a long hydrocarbon chain with a carboxyl group at one end. They are an important component of lipids and are involved in various biological processes such as energy storage, cell membrane structure, and signaling.