Question 1

Differences among organisms are caused by

Accepted Answer

A)   large differences in elemental composition from organism to organism.
B)   differences in the types and relative amounts of organic molecules synthesized by each organism.
C)   differences in the elements that bond with carbon in each organism.
D)   differences in the sizes of the organic molecules in each organism.
E)   differences in the inorganic compounds present in each organism.

Question 2

The complexity and variety of organic molecules is due to

Accepted Answer

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.

Question 3

Figure 3.4
-Which of the groups shown in Figure 3.4 is a functional group that helps stabilize proteins by forming covalent cross-links within or between protein molecules?

Accepted Answer

A)   A
B)   B
C)   C
D)   D
E)   E

Question 4

A compound contains hydroxyl groups as its predominant functional group. Which of the following statements is true concerning this compound?

Accepted Answer

A)   It lacks an asymmetric carbon, and it is probably a fat or lipid.
B)   It should dissolve in water.
C)   It should dissolve in a nonpolar solvent.
D)   It won't form hydrogen bonds with water.
E)   It is hydrophobic. B

Question 5

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?

Accepted Answer

A)   C60H120O60
B)   C6H12O6
C)   C60H102O51
D)   C60H100O50
E)   C60H111O51

Question 6

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

Accepted Answer

A)   phospholipids
B)   DNA
C)   RNA
D)   both DNA and RNA
E)   proteins

Question 7

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

Accepted Answer

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.

Question 8

Dehydration reactions are used in forming which of the following compounds?

Accepted Answer

A)   triacylglycerides
B)   polysaccharides
C)   proteins
D)   triacylglycerides and proteins only
E)   triacylglycerides, polysaccharides, and proteins

Question 9

Which chemical group is most likely to be responsible for an organic molecule behaving as a base (see Concept 2.5) ?

Accepted Answer

A)   hydroxyl
B)   carbonyl
C)   carboxyl
D)   amino
E)   phosphate

Question 10

Testosterone and estradiol are male and female sex hormones, respectively, in many vertebrates. In what way(s)  do these molecules differ from each other?

Accepted Answer

A)   Testosterone and estradiol are structural isomers but have the same molecular formula.
B)   Testosterone and estradiol are cis-trans isomers but have the same molecular formula.
C)   Testosterone and estradiol have different functional groups attached to the same carbon skeleton.
D)   Testosterone and estradiol have distinctly different chemical structures, with one including four fused rings of carbon atoms, whereas the other has three rings.
E)   Testosterone and estradiol are enantiomers of the same organic molecule.

Question 11

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

Accepted Answer

A)   hydrophobic interactions
B)   disulfide bonds
C)   ionic bonds
D)   hydrogen bonds
E)   peptide bonds

Question 12

Figure 3.5
-Which molecule shown in Figure 3.5 would have a positive charge in a cell?

Accepted Answer

A)   A
B)   B
C)   C
D)   D
E)   E

Question 13

Figure 3.7
-Which of the following descriptors is true of the molecule shown in Figure 3.7?

Accepted Answer

A)   hexose
B)   fructose
C)   glucose
D)   hexose and fructose only
E)   hexose and glucose only E

Question 14

Which of the following is not a polymer?

Accepted Answer

A)   glucose
B)   starch
C)   cellulose
D)   chitin
E)   DNA

Question 15

Which of these molecules is not formed by dehydration reactions?

Accepted Answer

A)   fatty acids
B)   disaccharides
C)   DNA
D)   protein
E)   amylose

Question 16

Figure 3.9
-Which of the following statements is true regarding the molecule illustrated in Figure 3.9?

Accepted Answer

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.

Question 17

A chemist wishes to make an organic molecule less acidic. Which of the following functional groups should be added to the molecule in order to do so?

Accepted Answer

A)   carboxyl
B)   sulfhydryl
C)   hydroxyl
D)   amino
E)   phosphate D

Question 18

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

Accepted Answer

A)   cellulose
B)   polypeptides
C)   starch
D)   amylopectin
E)   chitin

Question 19

The structural level of a protein least affected by a disruption in hydrogen bonding is the

Accepted Answer

A)   primary level.
B)   secondary level.
C)   tertiary level.
D)   quaternary level.
E)   All structural levels are equally affected.

Question 20

What is the structural feature that allows DNA to replicate?

Accepted Answer

A)   sugar-phosphate backbone
B)   complementary pairing of the nitrogenous bases
C)   disulfide bonding (bridging)  of the two helixes
D)   twisting of the molecule to form an α helix
E)   three-component structure of the nucleotides

Exam 3: Carbon and the Molecular Diversity of Life

Differences among organisms are caused by

Correct AnswerverifiedShow Answer

The complexity and variety of organic molecules is due to

Correct AnswerverifiedShow Answer

Figure 3.4 -Which of the groups shown in Figure 3.4 is a functional group that helps stabilize proteins by forming covalent cross-links within or between protein molecules?

Correct AnswerverifiedShow Answer

A compound contains hydroxyl groups as its predominant functional group. Which of the following statements is true concerning this compound?

Correct AnswerverifiedB

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?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Dehydration reactions are used in forming which of the following compounds?

Correct AnswerverifiedShow Answer

Which chemical group is most likely to be responsible for an organic molecule behaving as a base (see Concept 2.5) ?

Correct AnswerverifiedShow Answer

Testosterone and estradiol are male and female sex hormones, respectively, in many vertebrates. In what way(s) do these molecules differ from each other?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Figure 3.5 -Which molecule shown in Figure 3.5 would have a positive charge in a cell?

Correct AnswerverifiedShow Answer

Figure 3.7 -Which of the following descriptors is true of the molecule shown in Figure 3.7?

Correct AnswerverifiedE

Which of the following is not a polymer?

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Which of these molecules is not formed by dehydration reactions?

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Figure 3.9 -Which of the following statements is true regarding the molecule illustrated in Figure 3.9?

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A chemist wishes to make an organic molecule less acidic. Which of the following functional groups should be added to the molecule in order to do so?

Correct AnswerverifiedD

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

Correct AnswerverifiedShow Answer

The structural level of a protein least affected by a disruption in hydrogen bonding is the

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What is the structural feature that allows DNA to replicate?

Correct AnswerverifiedShow Answer

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B

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E

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D

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