AP Biology - Chemistry of Life Unit Exam

AP Biology - Chemistry of Life Unit Exam Multiple Choice Identify the choice that best completes the statement or answers the question. 1) About 25 o...
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AP Biology - Chemistry of Life Unit Exam Multiple Choice Identify the choice that best completes the statement or answers the question.

1) About 25 of the 92 natural elements are known to be essential to life. Which four of these 25 elements make up approximately 96% of living matter? A) carbon, sodium, hydrogen, nitrogen B) carbon, oxygen, phosphorus, hydrogen C) oxygen, hydrogen, calcium, nitrogen D) carbon, hydrogen, nitrogen, oxygen E) carbon, oxygen, nitrogen, calcium 2) Trace elements are those required by an organism in only minute quantities. Which of the following is a trace element that is required by humans and other vertebrates, but not by other organisms such as bacteria or plants? A) nitrogen B) calcium C) iodine D) sodium E) phosphorus 3) Why is each element unique and different from other elements in chemical properties? A) Each element has a unique atomic mass. B) Each element has a unique atomic weight. C) Each element has a unique number of protons in its nucleus. D) Each element has a unique number of neutrons in its nucleus. E) Each element has different radioactive properties. 4) The nucleus of a nitrogen atom contains 7 neutrons and 7 protons. Which of the following is a correct statement concerning nitrogen? A) The nitrogen atom has a mass number of approximately 7 daltons and an atomic mass of 14. B) The nitrogen atom has a mass number of approximately 14 daltons and an atomic mass of 7. C) The nitrogen atom has a mass number of 14 and an atomic mass of 7 grams. D) The nitrogen atom has a mass number of 7 and an atomic number of 14. E) The nitrogen atom has a mass number of 14 and an atomic mass of approximately 14 daltons. 5) An atom has 6 electrons in its outer shell. How many unpaired electrons does it have? A) 0 B) 2 C) 4 D) 6 E) 2 or 4

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6) Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that A) an electron may move to an electron shell farther away from the nucleus. B) an electron may move to an electron shell closer to the nucleus. C) the atom may become a radioactive isotope. D) the atom would become a positively charged ion, or cation, and become a radioactive isotope. E) the atom would become a negatively charged ion, or anion. 7) A covalent chemical bond is one in which A) electrons are removed from one atom and transferred to another atom so that the two atoms become oppositely charged. B) protons and neutrons are shared by two atoms so as to satisfy the requirements of both atoms. C) outer–shell electrons of two atoms are shared so as to satisfactorily fill the outer electron shells of both atoms. D) outer–shell electrons of one atom are transferred to fill the inner electron shell of another atom. E) an electron occupies a hybrid orbital located between the nuclei of two atoms. 8) What results from an unequal sharing of electrons between atoms? A) a nonpolar covalent bond B) a polar covalent bond C) an ionic bond D) a hydrogen bond E) a hydrophobic interaction 9) In comparing covalent bonds and ionic bonds, which of the following would you expect? A) An atom can form covalent bonds with multiple partner atoms, but only a single ionic bond with a single partner atom. B) Covalent bonds and ionic bonds occupy opposite ends of a continuous spectrum, from nearly equal to completely unequal sharing of electrons. C) Both involve electrical attraction between the electrons of one atom and the nucleus of the other atom. D) Ionic interactions remain when covalent bonds are broken in water. Ionic bonds are much stronger than covalent bonds. 10) Which of the following explains most specifically the attraction of water molecules to one another? A) nonpolar covalent bond B) polar covalent bond C) ionic bond D) hydrogen bond E) hydrophobic interaction

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11) Which of the following correctly describes chemical equilibrium? A) Forward and reverse reactions continue with no effect on the concentrations of the reactants and products. B) Concentrations of products are higher than the concentrations of the reactants. C) Forward and reverse reactions have stopped so that the concentration of the reactants equals the concentration of the products. D) Reactions stop only when all reactants have been converted to products. E) There are equal concentrations of reactants and products, and the reactions have stopped. 12)

Refer to the figure above (first three rows of the periodic table). If life arose on a planet where carbon is absent, which element might fill the role of carbon? A) boron B) silicon C) nitrogen D) aluminum E) phosphorus 13) A dietary Calorie equals 1 kilocalorie. Which of the following statements correctly defines 1 kilocalorie? A) 1,000 calories, or the amount of heat required to raise the temperature of 1 g of water by 1,000°C B) 100 calories, or the amount of heat required to raise the temperature of 100 g of water by 1°C C) 10,000 calories, or the amount of heat required to raise the temperature of 1 kg of water by 1°F D) 1,000 calories, or the amount of heat required to raise the temperature of 1 kg of water by 1°C E) 1,000 calories, or the amount of heat required to raise the temperature of 100 g of water by 100°C 3

14) Liquid water's high specific heat is mainly a consequence of the A) small size of the water molecules. B) high specific heat of oxygen and hydrogen atoms. C) absorption and release of heat when hydrogen bonds break and form. D) fact that water is a poor heat conductor. E) higher density of liquid water than solid water (ice). 15) Hydrophobic substances such as vegetable oil are A) nonpolar substances that repel water molecules. B) nonpolar substances that have an attraction for water molecules. C) polar substances that repel water molecules. D) polar substances that have an affinity for water. E) charged molecules that hydrogen–bond with water molecules. 16) The molar mass of glucose (C6H12O6) is 180 g/mol. Which of the following procedures should you carry out to make a 0.5 M solution of glucose? A) Dissolve 0.5 g of glucose in a small volume of water, and then add more water until the total volume of solution is 1 L. B) Dissolve 90 g of glucose in a small volume of water, and then add more water until the total volume of the solution is 1 L. C) Dissolve 180 g of glucose in a small volume of water, and then add more water until the total volume of the solution is 1 L. D) Dissolve 0.5 g of glucose in 1 L of water. E) Dissolve 180 g of glucose in 0.5 L of water. 17) A solution contains 0.0000001(10–7) moles of hydroxyl ions [OH–] per liter. Which of the following best describes this solution? A) acidic: H+ acceptor B) basic: H+ acceptor C) acidic: H+ donor D) basic: H+ donor E) neutral 18) If the pH of a solution is increased from pH 5 to pH 7, it means that the A) concentration of H+ is twice (2X) what it was at pH 5. B) concentration of H+ is one–half (1/2) what it was at pH 5. C) concentration of OH– is 100 times greater than what it was at pH 5. D) concentration of OH– is one–hundredth (0.01X) what it was at pH 5. E) concentration of H+ is 100 times greater and the concentration of OH – is one–hundredth what they were at pH 5. 19) Many mammals control their body temperature by sweating. Which property of water is most directly responsible for the ability of sweat to lower body temperature? A) water's change in density when it condenses B) water's ability to dissolve molecules in the air C) the release of heat by the formation of hydrogen bonds D) the absorption of heat by the breaking of hydrogen bonds E) water's high surface tension

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20) Which of the following is a hydrophobic material? A) paper B) table salt C) wax D) sugar E) pasta 21) The complexity and variety of organic molecules is due to A) the chemical versatility of carbon atoms. B) the variety of rare elements in organic molecules. C) the fact that they can be synthesized only in living organisms. D) their interaction with water. E) their tremendously large sizes. 22) How many electron pairs does carbon share in order to complete its valence shell? A) 1 B) 2 C) 3 D) 4 E) 8 23) A carbon atom is most likely to form what kind of bond(s) with other atoms? A) ionic B) hydrogen C) covalent D) covalent bonds and hydrogen bonds E) ionic bonds, covalent bonds, and hydrogen bonds 24) Which of the following statements correctly describes cis–trans isomers? A) They have variations in arrangement around a double bond. B) They have an asymmetric carbon that makes them mirror images. C) They have the same chemical properties. D) They have different molecular formulas. E) Their atoms and bonds are arranged in different sequences. 25) Amino acids are acids because they always possess which functional group? A) amino B) carbonyl C) carboxyl D) phosphate E) hydroxyl

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26)

The two molecules shown in the figure above are best described as A) optical isomers. B) enantiomers. C) structural isomers. D) cis–trans isomers. E) chain length isomers. 27) Thalidomide and L–dopa, shown below, are examples of pharmaceutical drugs that occur as enantiomers, or molecules that

A) B) C) D) E)

have identical three–dimensional shapes. are mirror images of one another. are structural isomers. are mirror images of one another and have the same biological activity. are cis–trans isomers.

28) Which functional group shown above is characteristic of alcohols? A) A B) B C) C D) D E) E

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29) Which functional group(s) shown above is (are) present in all amino acids? A) A and B B) B and D C) C only D) D only E) C and D 30) Which of the groups shown above is a carbonyl functional group? A) A B) B C) C D) D E) E

31) Which molecule shown above has a carbonyl functional group in the form of a ketone? A) A B) B C) C D) D E) E 32) Which molecule shown above contains a carboxyl group? A) A B) B C) C D) D E) E 33) Organic chemistry is currently defined as A) the study of compounds made only by living cells. B) the study of carbon compounds. C) the study of vital forces. D) the study of natural (as opposed to synthetic) compounds. E) the study of hydrocarbons.

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34) Which of these molecules is not formed by dehydration reactions? A) fatty acids B) disaccharides C) DNA D) protein E) amylose 35) What is the chemical reaction mechanism by which cells make polymers from monomers? A) phosphodiester linkages B) hydrolysis C) dehydration reactions D) ionic bonding of monomers E) the formation of disulfide bridges between monomers 36) Which of the following best summarizes the relationship between dehydration reactions and hydrolysis? A) Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers. B) Dehydration reactions eliminate water from lipid membranes, and hydrolysis makes lipid membranes water permeable. C) Dehydration reactions can occur only after hydrolysis. D) Hydrolysis creates monomers, and dehydration reactions break down polymers. E) Dehydration reactions ionize water molecules and add hydroxyl groups to polymers; hydrolysis reactions release hydroxyl groups from polymers. 37) On food packages, to what does the term insoluble fiber refer? A) cellulose B) polypeptides C) starch D) amylopectin E) chitin 38) Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified? A) as a pentose B) as a hexose C) as a monosaccharide D) as a disaccharide E) as a polysaccharide 39) Which of the following statements concerning saturated fats is not true? A) They are more common in animals than in plants. B) They have multiple double bonds in the carbon chains of their fatty acids. C) They generally solidify at room temperature. D) They contain more hydrogen than unsaturated fats having the same number of carbon atoms. E) They are one of several factors that contribute to atherosclerosis.

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40) Which of the following statements is true for the class of biological molecules known as lipids? A) They are insoluble in water. B) They are made from glycerol, fatty acids, and phosphate. C) They contain less energy than proteins and carbohydrates. D) They are made by dehydration reactions. E) They contain nitrogen. 41) Polysaccharides, triacylglycerides, and proteins are similar in that they A) are synthesized from monomers by the process of hydrolysis. B) are synthesized from subunits by dehydration reactions. C) are synthesized as a result of peptide bond formation between monomers. D) are decomposed into their subunits by dehydration reactions. E) all contain nitrogen in their monomer building blocks. 42) What aspects of protein structure are stabilized or assisted by hydrogen bonds? A) primary structure B) secondary structure C) tertiary structure D) quaternary structure E) secondary, tertiary, and quaternary structures, but not primary structure 43) Which level of protein structure do the  helix and the  pleated sheet represent? A) primary B) secondary C) tertiary D) quaternary E) primary, secondary, tertiary, and quaternary 44) What type of covalent bond between amino acid side chains (R groups) functions in maintaining a polypeptide's specific three–dimensional shape? A) ionic bond B) hydrophobic interaction C) van der Waals interaction D) disulfide bond E) hydrogen bond 45) Which of the following descriptions best fits the class of molecules known as nucleotides? A) a nitrogenous base and a phosphate group B) a nitrogenous base and a pentose sugar C) a nitrogenous base, a phosphate group, and a pentose sugar D) a phosphate group and an adenine or uracil E) a pentose sugar and a purine or pyrimidine 46) If one strand of a DNA molecule has the sequence of bases 5'ATTGCA3', the other complementary strand would have the sequence A) 5'TAACGT3'. B) 5'TGCAAT3'. C) 5'UAACGU3'. D) 3'UAACGU5'. E) 5'UGCAAU3'. 9

47) Which of the following is not a monomer/polymer pairing? A) monosaccharide/polysaccharide B) amino acid/protein C) triglyceride/phospholipid bilayer D) deoxyribonucleotide/DNA E) ribonucleotide/RNA

48) Which of the following statements is true regarding the molecule illustrated in Figure 5.3? A) It is a saturated fatty acid. B) A diet rich in this molecule may contribute to atherosclerosis. C) Molecules of this type are usually liquid at room temperature. D) It is a saturated fatty acid and a diet rich in this molecule may contribute to atherosclerosis. E) It is a saturated fatty acid, a diet rich in this molecule may contribute to atherosclerosis, and molecules of this type are usually liquid at room temperature. 49)

Which of the following statements is/are true regarding the chemical reaction illustrated in Figure 5.5? A) It is a hydrolysis reaction. B) It results in a peptide bond. C) It joins two fatty acids together. D) It is a hydrolysis reaction and it results in a peptide bond. E) It is a hydrolysis reaction, it results in a peptide bond, and it joins two fatty acids together.

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50) The structural level of a protein least affected by a disruption in hydrogen bonding is the A) primary level. B) secondary level. C) tertiary level. D) quaternary level. E) All structural levels are equally affected.

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ID: A

AP Biology - Chemistry of Life Unit Exam Answer Section MULTIPLE CHOICE 1) ANS: BNK: 2) ANS: BNK: 3) ANS: BNK: 4) ANS: BNK: 5) ANS: BNK: 6) ANS: BNK: 7) ANS: BNK: 8) ANS: BNK: 9) ANS: BNK: 10) ANS: BNK: 11) ANS: BNK: 12) ANS: BNK: 13) ANS: BNK: 14) ANS: BNK: 15) ANS: BNK: 16) ANS: BNK: 17) ANS: BNK: 18) ANS: BNK: 19) ANS: BNK:

D TOP: Concept 2.1 MSC: Knowledge/Comprehension Chapter 2—The Chemical Context of Life C TOP: Concept 2.1 MSC: Knowledge/Comprehension Chapter 2—The Chemical Context of Life C TOP: Concept 2.2 MSC: Knowledge/Comprehension Chapter 2—The Chemical Context of Life E TOP: Concept 2.2 MSC: Knowledge/Comprehension Chapter 2—The Chemical Context of Life B TOP: Concept 2.2 MSC: Knowledge/Comprehension Chapter 2—The Chemical Context of Life A TOP: Concept 2.2 MSC: Knowledge/Comprehension Chapter 2—The Chemical Context of Life C TOP: Concept 2.3 MSC: Knowledge/Comprehension Chapter 2—The Chemical Context of Life B TOP: Concept 2.3 MSC: Knowledge/Comprehension Chapter 2—The Chemical Context of Life B TOP: Concept 2.3 MSC: Synthesis/Evaluation Chapter 2—The Chemical Context of Life D TOP: Concept 2.3 MSC: Knowledge/Comprehension Chapter 2—The Chemical Context of Life A TOP: Concept 2.4 MSC: Knowledge/Comprehension Chapter 2—The Chemical Context of Life B TOP: Concept 2.2 MSC: Synthesis/Evaluation Chapter 2—The Chemical Context of Life D TOP: Concept 3.2 MSC: Knowledge/Comprehension Chapter 3—Water and Life C TOP: Concept 3.2 MSC: Knowledge/Comprehension Chapter 3—Water and Life A TOP: Concept 3.2 MSC: Knowledge/Comprehension Chapter 3—Water and Life B TOP: Concept 3.2 MSC: Application/Analysis Chapter 3—Water and Life E TOP: Concept 3.3 MSC: Application/Analysis Chapter 3—Water and Life C TOP: Concept 3.3 MSC: Application/Analysis Chapter 3—Water and Life D TOP: End–of–Chapter Questions MSC: Knowledge/Comprehension Chapter 3—Water and Life 1

ID: A

20) ANS: BNK: 21) ANS: BNK: 22) ANS: BNK: 23) ANS: BNK: 24) ANS: BNK: 25) ANS: BNK: 26) ANS: BNK: 27) ANS: BNK: 28) ANS: BNK: 29) ANS: BNK: 30) ANS: BNK: 31) ANS: BNK: 32) ANS: BNK: 33) ANS: BNK: 34) ANS: BNK: 35) ANS: BNK: 36) ANS: BNK: 37) ANS: BNK: 38) ANS: BNK: 39) ANS: BNK: 40) ANS: BNK:

C TOP: End–of–Chapter Questions MSC: Knowledge/Comprehension Chapter 3—Water and Life A TOP: Concept 4.1 MSC: Knowledge/Comprehension Chapter 4—Carbon and the Molecular Diversity of Life D TOP: Concept 4.2 MSC: Knowledge/Comprehension Chapter 4—Carbon and the Molecular Diversity of Life C TOP: Concept 4.2 MSC: Knowledge/Comprehension Chapter 4—Carbon and the Molecular Diversity of Life A TOP: Concept 4.2 MSC: Knowledge/Comprehension Chapter 4—Carbon and the Molecular Diversity of Life C TOP: Concept 4.3 MSC: Knowledge/Comprehension Chapter 4—Carbon and the Molecular Diversity of Life C TOP: Concept 4.2 MSC: Knowledge/Comprehension Chapter 4—Carbon and the Molecular Diversity of Life B TOP: Concept 4.2 MSC: Knowledge/Comprehension Chapter 4—Carbon and the Molecular Diversity of Life A TOP: Concept 4.3 MSC: Knowledge/Comprehension Chapter 4—Carbon and the Molecular Diversity of Life E TOP: Concept 4.3 MSC: Knowledge/Comprehension Chapter 4—Carbon and the Molecular Diversity of Life B TOP: Concept 4.3 MSC: Knowledge/Comprehension Chapter 4—Carbon and the Molecular Diversity of Life C TOP: Concept 4.3 MSC: Knowledge/Comprehension Chapter 4—Carbon and the Molecular Diversity of Life D TOP: Concept 4.3 MSC: Knowledge/Comprehension Chapter 4—Carbon and the Molecular Diversity of Life B TOP: End–of–Chapter Questions MSC: Knowledge/Comprehension Chapter 4—Carbon and the Molecular Diversity of Life A TOP: Concept 5.1 MSC: Knowledge/Comprehension Chapter 5—The Structure and Function of Large Biological Molecules C TOP: Concept 5.1 MSC: Knowledge/Comprehension Chapter 5—The Structure and Function of Large Biological Molecules A TOP: Concept 5.1 MSC: Knowledge/Comprehension Chapter 5—The Structure and Function of Large Biological Molecules A TOP: Concept 5.2 MSC: Knowledge/Comprehension Chapter 5—The Structure and Function of Large Biological Molecules D TOP: Concept 5.2 MSC: Knowledge/Comprehension Chapter 5—The Structure and Function of Large Biological Molecules B TOP: Concept 5.3 MSC: Knowledge/Comprehension Chapter 5—The Structure and Function of Large Biological Molecules A TOP: Concept 5.3 MSC: Knowledge/Comprehension Chapter 5—The Structure and Function of Large Biological Molecules

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ID: A

41) ANS: MSC: BNK: 42) ANS: BNK: 43) ANS: BNK: 44) ANS: BNK: 45) ANS: BNK: 46) ANS: BNK: 47) ANS: MSC: BNK: 48) ANS: BNK: 49) ANS: BNK: 50) ANS: BNK:

B TOP: Concept 5.1 | Concept 5.2 | Concept 5.3 | Concept 5.4 Application/Analysis Chapter 5—The Structure and Function of Large Biological Molecules E TOP: Concept 5.4 MSC: Knowledge/Comprehension Chapter 5—The Structure and Function of Large Biological Molecules B TOP: Concept 5.4 MSC: Knowledge/Comprehension Chapter 5—The Structure and Function of Large Biological Molecules D TOP: Concept 5.4 MSC: Knowledge/Comprehension Chapter 5—The Structure and Function of Large Biological Molecules C TOP: Concept 5.5 MSC: Knowledge/Comprehension Chapter 5—The Structure and Function of Large Biological Molecules B TOP: Concept 5.5 MSC: Application/Analysis Chapter 5—The Structure and Function of Large Biological Molecules C TOP: Concept 5.2 | Concept 5.3 | Concept 5.4 | Concept 5.5 Knowledge/Comprehension Chapter 5—The Structure and Function of Large Biological Molecules C TOP: Concept 5.3 MSC: Knowledge/Comprehension Chapter 5—The Structure and Function of Large Biological Molecules B TOP: Concept 5.4 MSC: Application/Analysis Chapter 5—The Structure and Function of Large Biological Molecules A TOP: End–of–Chapter Questions MSC: Knowledge/Comprehension Chapter 5—The Structure and Function of Large Biological Molecules

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