1.
Which of the following is a polymer of amino acids?
Correct Answer
A. Protein
Explanation
Protein is a polymer of amino acids. Amino acids are the building blocks of proteins, and when they join together through peptide bonds, they form long chains called polypeptides. These polypeptides then fold and interact to form functional proteins. Carbohydrates, lipids, and nucleic acids are not polymers of amino acids.
2.
Which of the following is a polymer of nucleotides?
Correct Answer
A. Nucleic Acid
Explanation
Nucleic Acid is the correct answer because it is a polymer of nucleotides. Nucleic acids are macromolecules that store and transmit genetic information in living organisms. They are made up of long chains of nucleotides, which consist of a sugar molecule, a phosphate group, and a nitrogenous base. The sequence of nucleotides in a nucleic acid determines the genetic code and plays a crucial role in protein synthesis and the functioning of cells. Proteins, carbohydrates, and lipids are not polymers 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 monomers combine through dehydration synthesis, where the hydroxyl group of glycerol reacts with the carboxyl group of a fatty acid, forming an ester bond. This process repeats multiple times, resulting in the formation of a lipid molecule, such as a triglyceride. Therefore, glycerol and fatty acids are the correct monomers that make up a lipid.
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. Instead, it is a nucleotide found in RNA. DNA is composed of four nucleotides: adenine, cytosine, guanine, and thymine. Thymine is the nucleotide that pairs with adenine in DNA, while uracil pairs with adenine in RNA. Therefore, uracil is not a nucleotide found in DNA.
5.
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. These amino acids are used to synthesize proteins, which play crucial roles in cell structure, function, and regulation. Each amino acid has a unique structure and function, allowing for the diverse range of proteins needed for human life.
6.
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. This refers to the chemical structure of the fat molecule, where all available carbon atoms are bonded to hydrogen atoms. In saturated fats, there are no double bonds between carbon atoms, and the carbon chain is fully "saturated" with hydrogen atoms. This is in contrast to unsaturated fats, which have one or more double bonds between carbon atoms and are not fully saturated with hydrogen atoms.
7.
Organic compounds always contain the element ____.
Correct Answer
A. Carbon
Explanation
Organic compounds always contain the element carbon. This is because carbon has the unique ability to form covalent bonds with other carbon atoms and a wide range of other elements, allowing for the formation of complex and diverse organic molecules. Carbon is the backbone of organic chemistry and is essential for the existence of life on Earth.
8.
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 bonds that connect 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, resulting in the formation of a peptide bond and the release of a water molecule. Peptide bonds play a crucial role in determining the structure and function of proteins.
9.
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 carbon atoms to form stable covalent bonds with other carbon atoms and with atoms of other elements. This versatility of carbon bonding enables the formation of a wide variety of organic molecules with different structures and properties.
10.
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 given statement is false. While it is true that there is a limited number of proteins that can be formed, it does not necessarily mean that life elsewhere in the universe will look exactly like life on Earth. Life on other planets may have different combinations of these proteins or even use different building blocks altogether. Additionally, the conditions and environments on other planets may vary significantly from Earth, leading to the possibility of different forms of life.
11.
The specific chemical that an enzyme will act on is called a(n) ...
Correct Answer
A. Substrate.
Explanation
Enzymes are proteins that act as catalysts in biological reactions. They speed up the rate of these reactions by binding to specific molecules called substrates. The enzyme's active site is complementary in shape to its specific substrate, allowing them to bind together. This binding facilitates the conversion of the substrate into a product. Therefore, the specific chemical that an enzyme acts on is called a substrate.
12.
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 decreasing the activation energy, the catalyst provides an alternative pathway for the reaction to proceed at a faster rate. This means that the reaction can happen more easily and quickly, without requiring additional energy or increasing the temperature. Therefore, the correct answer is "decreases the activation energy."
13.
What type of polymer is an enzyme?
Correct Answer
A. Protein
Explanation
Enzymes are biological catalysts that speed up chemical reactions in living organisms. Proteins are the most common type of polymer that enzymes are made of. Proteins are composed of long chains of amino acids, which fold into specific three-dimensional structures. This unique structure allows enzymes to bind to specific substrates and facilitate chemical reactions. Therefore, the correct answer is protein.
14.
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 such as DNA and RNA. It is a 5-carbon sugar that forms the backbone of the nucleotide molecule. In this question, the part labeled B is likely referring to the ribose sugar.
15.
What part is labeled C?
Correct Answer
C. Nitrogen Base
Explanation
Nitrogen bases are the organic molecules that make up the building blocks of DNA and RNA. They are responsible for carrying the genetic information in the form of nucleotides. In this question, the options provided are different components of a nucleotide, and the correct answer is "Nitrogen Base" because it represents the specific molecule that forms the genetic code. Phosphate represents the phosphate group, ribose sugar represents the sugar molecule, and nucleotide represents the complete unit consisting of a phosphate group, sugar molecule, and nitrogen base.
16.
What part is labeled A?
Correct Answer
A. pHospHate
Explanation
The part labeled A in this question is the phosphate. Phosphate is an essential component of a nucleotide, which is the building block of DNA and RNA. It plays a crucial role in the structure and function of nucleic acids by providing a negative charge and contributing to the stability of the molecule.
17.
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 combines to form a larger molecule. In this case, the diagram likely shows a phosphate group, a ribose sugar, and a nitrogen base, which are the components of a nucleotide. Nucleotides are the building blocks of nucleic acids, such as DNA and RNA. Therefore, the correct answer is "Nucleotide."
18.
The name of a sugar typically ends with the suffix -ose.
Correct Answer
A. True
Explanation
The statement is true because the suffix -ose is commonly used to indicate a sugar in the name of a compound. For example, glucose, fructose, and sucrose are all sugars that end with -ose. This naming convention helps to identify and classify different types of sugars based on their chemical structure and properties.
19.
The structure labeled A is called ___.
Correct Answer
A. Glycerol
Explanation
The structure labeled A is called glycerol because it has a three-carbon backbone with hydroxyl groups attached to each carbon. Glycerol is a 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 structures and functions.
20.
The structures labeled B are ___.
Correct Answer
A. Fatty acids
Explanation
The structures labeled B are fatty acids. Fatty acids are organic molecules composed of a 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 and cell membrane formation.
21.
The ___ form of this molecule is found in animals and is ___ at room temperature.
Correct Answer
A. Saturated ... solid
Explanation
Saturated forms of molecules have all of their carbon atoms bonded to the maximum number of hydrogen atoms, resulting in a stable structure. This stability allows saturated molecules to exist in a solid state at room temperature. Therefore, the correct answer is "saturated ... solid."
22.
Which phrase best describes atoms?
Correct Answer
A. Smallest basic unit of matter
Explanation
Atoms are the smallest basic units of matter. They are the building blocks of all substances and cannot be broken down further without losing their chemical properties. Atoms consist of a nucleus, which contains positively charged particles called protons and uncharged particles called neutrons. Surrounding the nucleus are negatively charged particles called electrons. Therefore, the phrase "smallest basic unit of matter" accurately describes atoms.
23.
Which of the following cannot be broken down by ordinary chemical means?
Correct Answer
A. Element
Explanation
An element cannot be broken down by ordinary chemical means because it is a pure substance made up of only one type of atom. Chemical reactions can break down compounds into simpler substances, molecules into atoms, and bonds between atoms, but elements remain unchanged.
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 around the nucleus of an atom. When an atom gains or loses electrons, it becomes electrically charged and forms an ion. Gaining electrons results in a negative ion (anion) as the atom now has more electrons than protons, while losing electrons leads to a positive ion (cation) as the atom now has fewer electrons than protons. Protons and neutrons are particles found in the nucleus of an atom and are not involved in the formation of ions. Photons, on the other hand, are particles of light and have no role in ion formation.
25.
Atoms connected by covalent bonds share
Correct Answer
A. Pairs of electrons
Explanation
Covalent bonds occur when atoms share pairs of electrons. In a covalent bond, two atoms share one or more pairs of electrons, which allows them to achieve a more stable electron configuration. This sharing of electrons creates a strong bond between the atoms, resulting in the formation of a molecule. Therefore, the correct answer is "pairs of electrons."
26.
Which molecules store and transmit genetic information?
Correct Answer
C. Nucleic acids
Explanation
Nucleic acids store and transmit genetic information. They are made up of long chains of nucleotides, which contain the genetic code in the form of DNA or RNA. DNA carries the instructions for the development and functioning of all living organisms, while RNA plays a crucial role in protein synthesis. Lipids, proteins, and carbohydrates are important molecules in cellular processes, but they do not primarily store or 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 nitrogen bases, namely adenine (A), guanine (G), cytosine (C), and thymine (T) in DNA or uracil (U) in RNA, are essential for the genetic information storage and transfer. Nucleic acids, including DNA and RNA, play a crucial role in encoding and transmitting genetic information in living organisms. They are composed of nucleotides, which consist of a nitrogenous base, a sugar molecule, and a phosphate group. Therefore, nucleic acids are the correct answer to the question.
28.
The molecule illustrated here is a monomer of what macromolecule?
Correct Answer
C. Nucleic acid
Explanation
The molecule illustrated is a monomer of a nucleic acid. Nucleic acids are macromolecules that store and transmit genetic information. They are made up of monomers called nucleotides, which consist of a sugar, a phosphate group, and a nitrogenous base. The molecule in the illustration appears to have a sugar (possibly ribose or deoxyribose), a phosphate group, and a nitrogenous base, indicating that it is a nucleotide and therefore a monomer of a nucleic acid.
29.
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 partial positive charge on one side and a partial negative charge on the other. This polarity allows water to dissolve other polar substances, making it an excellent solvent. Adhesion refers to water's ability to stick to other surfaces, while cohesion refers to water's ability to stick to itself. Both of these properties are important for many biological processes. Lastly, water has a high specific heat, meaning it can absorb and retain a large amount of heat without a significant change in temperature. This property is important for regulating temperature in living organisms.
30.
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. The concentration of H+ ions determines the acidity of a solution, with higher concentrations indicating higher acidity. A pH of 7 is considered neutral, so it cannot be the correct answer. Killing all organisms is not necessarily related to the concentration of H+ ions, so it is not the correct answer. Having a high pH indicates a low concentration of H+ ions, so it is also not the correct answer. Therefore, the correct answer is that a solution with a high concentration of H+ ions is very acidic.
31.
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, with a ratio of hydrogen to oxygen atoms of 2:1. Sugars and starches are both types of carbohydrates, with sugars being simple carbohydrates and starches being complex carbohydrates. Carbohydrates are an essential source of energy for living organisms and play a crucial role in various biological processes.
32.
Identify the reactants in this chemical equation.
Correct Answer
A. Carbon dioxide and water
Explanation
The reactants in this chemical equation are carbon dioxide and water. This can be determined by analyzing the given options. The other options, such as sugar and oxygen, carbon dioxide and oxygen, and sunlight and water, do not match the reactants in the equation.
33.
Fats, oils, and cholesterol are all types of ___.
Correct Answer
C. Lipids
Explanation
Fats, oils, and cholesterol are all types of lipids. Lipids are a group of organic compounds that are insoluble in water but soluble in organic solvents. They are an essential component of our diet and play a vital role in energy storage, insulation, and protection of organs. Fats and oils are examples of triglycerides, which are the main form of stored energy in the body. Cholesterol is a type of lipid that is important for the production of hormones and cell membranes. Therefore, lipids are the correct answer.
34.
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) carries the genetic instructions for the development, functioning, and reproduction of all known organisms, while RNA (ribonucleic acid) plays a crucial role in protein synthesis and gene expression. Both DNA and RNA are composed of nucleotides, which are the building blocks of nucleic acids. Therefore, nucleic acids is the correct answer.
35.
Enzymes are a type of ___.
Correct Answer
B. Protein
Explanation
Enzymes are a type of protein. Proteins are macromolecules made up of amino acids, and enzymes are a specific type of protein that act as catalysts in biological reactions. They speed up chemical reactions by lowering the activation energy required for the reaction to occur. Enzymes play a crucial role in various biological processes, such as digestion, metabolism, and cellular signaling.
36.
Identify the products in this chemical equation.
Correct Answer
B. Sugar and oxygen
Explanation
The products in this chemical equation are sugar and oxygen. This can be determined by analyzing the reactants and the products. The given equation does not mention any reactants, but it does mention carbon dioxide and water as options for the products. However, carbon dioxide and water are not the correct products in this case. The correct products are sugar and oxygen, as indicated in the answer.
37.
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 is the term used to describe the amount of energy that needs to be added for a chemical reaction to start. It is the minimum energy required to break the 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 the reaction to proceed, and it determines the rate at which the reaction occurs. Without sufficient activation energy, the reaction will not take place.
38.
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. In this type of reaction, the products have lower energy than the reactants, resulting in a release of energy in the form of heat or light. This is in contrast to an endothermic reaction, where the products have higher energy than the reactants and therefore absorb energy from the surroundings.
39.
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 reaction pathway with a lower activation energy. This lowers the energy barrier for the reactants to transform into products, allowing the reaction to occur more quickly. Therefore, the phrase "increases the reaction rate" best describes the effect of a catalyst on a chemical reaction.
40.
The specific reactants that an enzyme acts on are called ___.
Correct Answer
C. Substrates
Explanation
Enzymes are proteins that catalyze chemical reactions in living organisms. They bind to specific molecules called substrates and facilitate the conversion of substrates into products. Therefore, the correct answer is "substrates" because it refers to the specific reactants that an enzyme acts on.
41.
This graph represents ___.
Correct Answer
C. Enzyme activity
Explanation
The graph represents enzyme activity because it shows a gradual increase in the rate of reaction over time. Enzymes are biological catalysts that speed up chemical reactions in living organisms. The graph's upward trend indicates that as time progresses, the enzyme activity increases, resulting in a higher rate of reaction.
42.
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 means that it consists of repeating units called monomers, which are chemically bonded together to form a larger structure. Polymers can be found in various forms, such as plastics, fibers, and proteins. They have a wide range of applications in industries such as packaging, textiles, and medicine.
43.
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 can join together through chemical reactions to form a polymer chain. Therefore, a monomer is a fundamental building block of a polymer.
44.
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 are typically smaller in size compared to the solvent particles, allowing them to mix and form a homogeneous mixture. This process is known as dissolution. The solute can be a solid, liquid, or gas, and examples include salt dissolving in water or sugar dissolving in coffee.
45.
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 typically present in a larger amount compared to the solute, making it the component with the greatest concentration in the solution.