exam review questions

Question 1

A molecule with the formula C18H36O2 is probably a

Answer 1

Fatty acid

Question 2

) Which of the following statements regarding lipids is true?

A) They generally contain nitrogen.

B) They are made from glycerol and amino acids.

C) A gram of lipid stores less energy than a gram of carbohydrate.

D) They are insoluble in water

Answer 2

They are insouble in water

Question 3

Hydrogenated vegetable oil is the primary ingredient in margarine. How does hydrogenated vegetable oil differ from nonhydrogenated vegetable oil?

A) Hydrogenated vegetable oil has a lower melting point than nonhydrogenated vegetable oil.

B) Hydrogenated vegetable oil is solid at room temperature, whereas nonhydrogenated vegetable oil is liquid.

C) Hydrogenated vegetable oil has more kinks in its fatty acid chains than does nonhydrogenated vegetable oil.

D) Hydrogenated vegetable oil contains more cis fatty acids than nonhydrogenated vegetable oil

Answer 3

B

Question 4

Which of the following statements regarding saturated fatty acids is true?

A) They are the predominant fatty acid in corn oil.

B) They have double bonds between the carbon atoms of the fatty acids.

C) They are the principal molecules in lard and butter.

D) They are usually liquid at room temperature.

E) They are usually produced by plants.

Answer 4

C

Question 5

Large organic molecules are generally synthesized by polymerization of a few types of simple subunits. Which of the following is an exception to this statement?

A) a steroid

B) cellulose

C) DNA

D) an enzyme

Answer 5

steroid

Question 6

Which of the following large biological molecules will self-assemble into a bilayer when mixed with water?

A) proteins

B) triacylglycerols

C) cellulose

D) phospholipids

Answer 6

Phospholipid

Question 7

Why are the vertebrate sex hormones estradiol and testosterone considered to be lipids?

A) They are essential components of cell membranes.

B) Their carbon skeletons are composed of primarily C–C and C–H bonds.

C) They are made of fatty acids.

D) They are hydrophilic compounds.

Answer 7

their carbon skeletons are composed of primarily C-C and C-H bonds

Question 8

Which of the following molecules lacks amino acids?

A) hemoglobin

B) insulin

C) antibodies

D) spider silk

E) cholesterol

Answer 8

Chlolesterol

Question 9

There are 20 different amino acids. What makes one amino acid different from another?

A) different side chains (R groups) attached to the carboxyl carbon

B) different side chains (R groups) attached to the amino groups

C) different side chains (R groups) attached to an α carbon

D) different asymmetric carbons

Answer 9

Different side chains attached to an α carbon

Question 10

Which bonds are created during the formation of the primary structure of a protein?

A) disulfide bonds

B) hydrogen bonds

C) peptide bonds

D) phosphodiester bonds

Answer 10

Peptide bonds

Question 11

Which bonds maintain the primary structure of a protein?

A) disulfide bonds

B) hydrogen bonds

C) ionic bonds

D) peptide bonds

Answer 11

Peptide bonds

Question 12

What maintains the secondary structure of a protein?

A) peptide bonds between adjacent amino acids

B) hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond

C) disulfide bonds between the amino group of one peptide bond and the R group of another amino acid

D) hydrogen bonds between the carboxyl group of one peptide bond and the R group of another amino acid

Answer 12

hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond

Question 13

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

A) hydrophobic interactions

B) ionic bonds

C) hydrogen bonds

D) peptide bonds

Answer 13

Hydrogen bonds

Question 14

The α helix and β pleated sheet are examples of which level of protein structure?

A) primary

B) secondary

C) tertiary

D) quaternary

E) primary, secondary, tertiary, and quaternary

Answer 14

Secondary

Question 15

Lactase is an enzyme composed of a single polypeptide that hydrolyzes the disaccharide lactose to produce monosaccharides. The optimal pH for lactase activity is 6. Transfer of lactase to pH 5 results in a substantial decrease in enzyme activity, likely due to the disruption of

A) only the primary structure of the enzyme.

B) the primary and secondary structure of the enzyme.

C) the secondary and tertiary structure of the enzyme.

D) the secondary, tertiary, and quaternary structure of the enzyme

Answer 15

the secondary and tertiary structure of the enzyme.

Polypetide forms through a heydration reaction

primary and tertiary structures are held together by

Question 16

Collagen is a protein made of three identical polypeptides composed primarily of α helix structure. The α helix is an example of

A) secondary structure stabilized by covalent bonds.

B) secondary structure stabilized by hydrogen bonds.

C) secondary structure stabilized by ionic bonds.

D) tertiary structure stabilized by covalent bonds.

E) tertiary structure stabilized by hydrogen bonds.

Answer 16

secondary structure stabilized by hydrogen bonds.

Question 17

The tertiary structure of a polypeptide is the

A) linear sequence of amino acids in a polypeptide.

B) localized region of a polypeptide chain that forms an α helix or β pleated sheet.

C) overall three-dimensional shape of a fully folded polypeptide.

D) overall three-dimensional shape of a protein composed of more than one polypeptide.

Answer 17

overall three-dimensional shape of a fully folded polypeptide.

Question 18

A disulfide bridge is an example of which type of bond?

A) ionic bond between R groups

B) hydrophobic interaction between R groups

C) hydrogen bond between R groups

D) covalent bond between R groups

Answer 18

D) covalent bond between R groups

Question 19

Interactions between the side chains (R groups) in a polypeptide are most important in stabilizing which of the following?

A) primary structure

B) secondary structure

C) tertiary structure

D) quaternary structure

Answer 19

D) quaternary structure

two polypetide chains in a quatery structure

Question 20

The side chain (R group) of the amino acid serine is –CH2–OH. The side chain of the amino acid leucine is –CH2–CH–(CH3)2. Where would you expect to find these amino acids in a globular protein in aqueous solution?

A) Serine would be on the exterior, and leucine would be in the interior of the globular protein.

B) Serine would be in the interior, and leucine would be on the exterior of the globular protein.

C) Both serine and leucine would be in the interior of the globular protein.

D) Both serine and leucine would be on the exterior of the globular protein.

Answer 20

Serine would be on the exterior, and leucine would be in the interior of the globular protein.

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Question 21

Changing a single amino acid in a protein consisting of 433 amino acids would

A) always alter the primary structure of the protein but never alter its tertiary structure or function.

B) always alter the primary structure of the protein and sometimes alter its tertiary structure or function.

C) always alter the primary and tertiary structure of the protein but never alter its function.

D) sometimes alter the primary and tertiary structure of the protein but always alter its function.

Answer 21

B) always alter the primary structure of the protein and sometimes alter its tertiary structure or function.

Question 22

Normal hemoglobin is a tetramer, consisting of two molecules of β-globin and two molecules of α-globin. In sickle-cell disease, as a result of a single amino acid change, the mutant hemoglobin tetramers associate with each other and assemble into large fibers. Based on this information alone, we can conclude that sickle-cell hemoglobin exhibits

A) altered primary structure.

B) altered secondary structure.

C) altered tertiary structure.

D) altered quaternary structure.

E) altered primary structure and altered quaternary structure; the secondary and tertiary structures may or may not be altered.

Answer 22

E) altered primary structure and altered quaternary structure; the secondary and tertiary structures may or may not be altered.

Question 23

In a normal cellular protein, where would you expect to find a hydrophilic amino acid such as asparagine?

A) in the interior of the folded protein, away from water

B) on the exterior surface of the protein, interacting with water

C) in the transmembrane portion interacting with lipid fatty acid chains

D) on the exterior surface of the protein, interacting with water, or in a transmembrane portion interacting with lipid fatty acid chains

Answer 23

on the exterior surface of the protein, interacting with water

Question 24

If cells are grown in a medium containing radioactive 35S, which of these molecules will be radioactively labeled?

A) phospholipids

B) nucleic acids

C) proteins

D) starch

Answer 24

Proteins

Question 25

If cells are grown in a medium containing radioactive 32P, which of these molecules will be radioactively labeled?

A) triacylglycerols

B) nucleic acids

C) fatty acids

D) starch

Answer 25

nucleic acids

Question 26

How will brief heating (to 95°C) affect macromolecular structures in aqueous solution?

A) Unsaturated fatty acid tails will become saturated.

B) Proteins will unfold (denature).

C) Starch will hydrolyze into monomeric sugars.

D) Proteins will hydrolyze into amino acids.

Answer 26

Proteins will unfold (denature

Question 27

Which of the following statements about the 5’ end of a polynucleotide strand of RNA is correct?

A) The 5’ end has a hydroxyl group attached to the number 5 carbon of ribose.

B) The 5’ end has a phosphate group attached to the number 5 carbon of ribose.

C) The 5’ end has phosphate attached to the number 5 carbon of the nitrogenous base.

D) The 5’ end has a nitrogenous base attached to the number 5 carbon of ribose.

Answer 27

The 5’ end has a phosphate group attached to the number 5 carbon of ribose.

Question 28

One of the primary functions of RNA molecules is to

A) transmit genetic information to offspring.

B) function in the synthesis of proteins.

C) make a copy of itself, thus ensuring genetic continuity.

D) act as a pattern or blueprint to form DNA.

Answer 28

Function in the sythesis of proteins

Question 29

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

A) polysaccharides

B) proteins

C) DNA

D) RNA

E) both DNA and RNA

Answer 29

Both DNA and RNA

Question 30

A nucleotide is composed of

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 nitrogenous base, a phosphate group, a pentose sugar, and an amino acid.

Answer 30

a nitrogenous base, a phosphate group, and a pentose sugar.

Question 31

Which of the following are pyrimidines?

A) adenine and thymine

B) adenine and guanine

C) cytosine and uracil

D) cytosine and guanine

Answer 31

adenine and guanine

purines

cytosine and thymine, uracil in RNA