Chapter 3

24) Which of the following can serve as an energy source and as structural support in plant cells?

A) Carbohydrates

25) Which of the following categories includes monosaccharide monomers?

A) Carbohydrates

64) Your friend is trying to learn about how to kill bacteria. She reads that preservatives such as citric 64) acid are added to foods because the acidic environment kills bacteria by denaturing their proteins. She thinks this sounds like a lot of scientific jargon and asks you what it means. How can you explain it in simpler terms?

A) Denaturing means that the proteins of the bacteria lose their structure and can't function, so the bacteria die.

31) When 1 gram of each of these food sources is consumed, which yields the greatest amount of energy in calories?

A) Fat

53) What maintains the secondary structure of a protein?

A) Hydrogen bonds

37) The fat substitute Olestra contains a sucrose backbone with six to eight fatty acids attached. How is this different from a naturally occurring fat?

A) Naturally occurring fats contain a glycerol and three

75) Which of these biological molecules contain genetic information?

A) Nucleic acids

58) Which of the following refers to the amino acid sequence of proteins?

A) Primary

61) Which of the following biological molecules are composed of amino acid subunits?

A) Proteins

62) Which of the following may possess primary, secondary, tertiary, and quaternary structures?

A) Proteins

9) In dehydration synthesis, the atoms that make up a water molecule come from

D) both of the reactants.

49) The specific function of a protein is determined by the

D) exact sequence of amino acids.

48) Proteins are constructed using how many different amino acids?

D) 20

7) Which of the following reactions is an example of dehydration synthesis?

D) Glucose + galactose → lactose

26) When the level of glucose in your blood is high, your body is able to store excess glucose in the liver by forming glycogen. When blood glucose levels fall, this stored glucose can be released.

D) Glycogen is a polysaccharide formed by joining excess monosaccharides of glucose.

73) Suppose you have discovered a new virus and have isolated its nucleic acids. What feature could you look for to determine whether the nucleic acids of this virus are RNA or DNA?

D) If it is RNA, it will contain ribose.

41) Which of the following biological molecules possess large nonpolar regions, making them insoluble in water?

D) Lipids

42) Which of the following groups is crucial to the structure and function of the sex hormones estrogen and testosterone?

D) Lipids

74) Which of the following biological molecules are composed of monomer units containing a sugar, a phosphate group, and a nitrogen-containing base?

D) Nucleic acids

63) Your classmate is trying to keep all the facts about biological molecules straight. He asks you to explain how amino acids and proteins are related. What do you tell him?

D) Proteins are made up of chains of amino acids.

79) In this scenario, how are the soap, dirt/oil, and water arranged at the molecular level?

D) The soap molecules encase the dirt/oil within a small droplet that has a hydrophilic exterior and a hydrophobic interior.

78) In this scenario, what is the most likely procedure beer makers use to produce alcohol from starchy 97) grains? A) The starch is converted into glycogen, which is easier for the yeast to digest. B) The starch is converted into a polymer of many glucose molecules before being used. C) Water is used to break the bonds between glucose subunits in the starch, in a form of dehydration synthesis. D) The starch is broken down into mono- and/or disaccharides by hydrolysis before use.

D) The starch is broken down into mono- and/or disaccharides by hydrolysis before use.

43) Which of the following is TRUE about waxes?

D) They are saturated fats and are solid at normal outdoor temperatures.

57) Which type of molecule is most abundant in a typical cell?

D) Water

36) All of the following lipids or lipid components are hydrophobic EXCEPT

D) fatty acid heads.

52) All of the following are polysaccharides EXCEPT

D) glucose.

60) A denatured protein differs from a normal protein because it

D) has lost its usual secondary and tertiary structures.

21) Which of the following provides long-term energy storage for plants?

A) Starch

47) Enzymes are specialized ________ that catalyze chemical reactions within the body.

D) proteins

33) What property of phospholipids makes them important in cell membranes?

B) They have a polar end and a nonpolar end.

15) The carbohydrate in DNA is

A) deoxyribose.

72) Which of these is NOT a nucleic acid or nucleotide?

A) LDL

70) Adenosine triphosphate (ATP) is an example of a(n)

B) nucleotide.

35) New government regulations require that foods containing trans fats be labeled appropriately. A trans fat is formed when food manufacturers turn liquid oils into solid fats by adding hydrogen to vegetable oils. This hydrogenation process produces a solid fat because adding the hydrogen

A) allows the fatty acid chains to pack together more tightly.

38) Two categories of organic compounds typically provide energy for living systems. Representatives of these two classes are

A) carbohydrates and proteins.

10) If digestion is ________, then synthesis is ________.

A) hydrolysis;dehydration synthesis

12) Keratin and silk are examples of ________, whereas glucose and maltose are examples of ________.

A) proteins; carbohydrates

4) Which of the following best explains the molecular complexity of living organisms?

B) A small number of monomers can be assembled into large polymers with many different

2) Which of the following is NOT an organic molecule?

B) Carbon monoxide

50) What do carbohydrates, lipids, and proteins have in common?

B) Covalent bonding holds these molecules together.

23) In humans, dental cavities form when Streptococcus mutans bacteria in the mouth hydrolyze sucrose. Which of the following is (are) the products of this reaction?

B) Glucose and fructose

56) Which of the following is an example of a protein?

B) Keratin

14) Which molecule is a disaccharide?

B) Lactose

39) Imagine that you have isolated a mysterious liquid from a sample of food. You add the liquid to a beaker of water and shake vigorously. After a few minutes, the water and the other liquid separate into two layers. To which class of biological molecules does the unknown liquid most likely belong?

B) Lipids

28) Which of the following is insoluble in water?

B) Olive oil

27) Which type of lipid is most important in biological membranes?

B) Phospholipid

65) Scientists consider prions to be "puzzling" proteins. Which of the following is TRUE about prions?

B) Prions are proteins that cause nearby proteins to change shape and become infectious.

66) Which of the following correctly matches an organic polymer with its monomers, respectively?

B) Protein;amino acids

11) Hydrolysis may be correctly described as the

B) breaking of a compound into its subunits by using water to break the bond between monomers.

54) Complex, three-dimensional, tertiary structures of proteins result from

B) hydrogen and disulfide bonds.

40) Cell membranes are an example of a lipid bilayer. In this lipid bilayer, both the outside of the cell and the inside of the cell are ________ in nature.

B) hydrophobic

71) A nucleotide is made of a

B) phosphate, sugar, and nitrogenous base.

18) Chitin is an example of a

B) polysaccharide.

3) You are telling your friend that organic molecules are all made up of carbon backbones with hydrogens. She doesn't understand how there can be so many different organic molecules if they all are made up of the same basic components. You explain that organic molecules

B) vary because they possess different functional groups.

5) Large biological molecules are synthesized by removing

B) water.

69) How many hydrogen bonds exist between a G-C base pair?

C) 3

6) What type of chemical reaction results in the breakdown of organic polymers into their respective subunits?

C) Hydrolysis

34) Lard is a solid fat at room temperature. What does this tell you about the triglycerides in lard?

C) Lard is composed of saturated fats.

55) The four polypeptides that are joined together to make functional hemoglobin represent which level of protein organization?

C) Quaternary structure

13) Dehydration synthesis involves the removal of a hydrogen ion and a hydroxyl ion. What happens next?

C) The hydrogen and hydroxyl ions combine to form water.

44) Which of the following statements about lipids is incorrect?

C) They are short chains of polar hydrocarbons.

20) An example of a structural polysaccharide is

C) cellulose

22) Lactose is a disaccharide of glucose and galactose, and its digestion requires the actions of the enzyme lactase. If lactose is eaten as part of the diet but is not digested by lactase, this sugar is then metabolized by bacteria in the intestine, leading to the symptoms of lactose intolerance. Lactose intolerance, therefore, results from a(n)

C) lack of hydrolysis of lactose.

30) Triglycerides are

C) made from glycerol and fatty acids.

29) Cholesterol, testosterone, and estrogen are examples of

C) steroids.

16) Maltose is made from

C) two glucose molecules.

45) HDL and LDL are different types of cholesterol found in the blood. These compounds are

D) lipids.

1) Prions are known to cause

D) mad cow disease.

46) The group of biological molecules that are most diverse in function is

D) proteins.

51) A peptide bond forms between which of these groups?

E) Carboxyl and amino

8) Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?

E) Dehydration reactions assemble polymers, and hydrolysis breaks them down.

19) Where is glycogen stored in vertebrate animals?

E) Liver and muscles

59) The bonding of two amino acid molecules to form a larger molecule requires which of the following?

E) Removal of a water molecule

17) The fiber in your diet is actually

E) cellulose.

68) DNA carries genetic information in its

E) sequence of bases.

67) The "backbone" of a nucleic acid molecule is made of

E) sugar and phosphate groups.

32) Fats and oils are made of

E) three fatty acids and one glycerol.

77) Phospholipids have hydrophilic tail regions and hydrophobic head regions.

FALSE

76) Functional groups determine the characteristics and chemical reactivity of organic molecules.

TRUE