Unit 2 Learning Catalytics

Which of the pairs of molecular structures shown below do NOT depict enantiomers (enantiomeric forms) of the same molecule?

Which of the functional groups below acts most like an acid in water?

1. amino

2. carbonyl

3. carboxyl

4. hydroxyl

3. carboxyl

Which of the structures illustrated below is an impossible covalently bonded molecule?

1. A

2. B

3. C

4. D

2. B

Which molecule shown below contains a functional group that cells use to transfer energy between organic molecules?

1. A

2. B

3. C

4. D

4. D

The molecular formula for glucose is C6H12O6. What would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions?

1. C18H36O18

2. C18H32O16

3. C6H10O5

4. C18H30O15

1. C18H32O16

How do phospholipids interact with water molecules?

1. The polar heads avoid water; the nonpolar tails attract water (because water is polar and opposites attract).

2. Phospholipids do not interact with water because water is polar and lipids are nonpolar.

3. The polar heads interact with water; the nonpolar tails do not.

4. Phospholipids dissolve in water.

3. The polar heads interact with water; the nonpolar tails do not.

Which of the following is the best explanation for why vegetable oil is a liquid at room temperature while animal fats are solid?

1. Vegetable oil has more double bonds than animal fats.

2. Vegetable oil has fewer double bonds than animal fats.

3. Animal fats have no amphipathic character.

4. Vegetable oil has longer fatty-acid tails than animal fats have.

1. Vegetable oil has more double bonds than animal fats.

You disrupt all hydrogen bonds in a protein. What level of structure will be preserved?

1. primary structure

2. secondary structure

3. tertiary structure

4. quaternary structure

1. primary structure

You have just sequenced a new protein found in mice and observe that sulfur-containing cysteine residues occur at regular intervals. What is the significance of this finding?

1. Cysteine residues are required for the formation of a-helices and b-pleated sheets.

2. It will be important to include cysteine in the diet of the mice.

3. Cysteine residues are involved in disulfide bridges that help form tertiary structure.

4. Cysteine causes bends, or angles, to occur in the tertiary structure of proteins.

3. Cysteine residues are involved in disulfide bridges that help form tertiary structure.

The R-group, or side chain, of the amino acid serine is -CH2-OH. The R-group, or 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?

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

2. Leucine would be in the interior, and serine would be on the exterior of the globular protein.

3. Serine and leucine would both be in the interior of the globular protein.

4. Serine and leucine would both be on the exterior of the globular protein.

2. Leucine would be in the interior, and serine would be on the exterior of the globular protein.

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

1. DNA

2. RNA

3. both DNA and RNA

4. proteins

2. RNA

If one strand of a DNA molecule has the sequence of bases 5'ATTGCA3', the other complementary strand would have the sequence _____.

1. 5'UGCAAU3'

2. 3'UAACGU5'

3. 5'TGCAAT3'

4. 5'TAACGT3'

3. 5'TGCAAT3'