Amino Acids

Question 1

In a biological environment, which of the following would produce an effect similar to that of BME on proteins?

a. H2O
b. FAD
c. GTP
d. NADPH

Answer 1

d. NADPH

Both are reducing agents

Question 2

What is the approximate mass of an amino acid within a protein?

Answer 2

110 Da

Question 3

Which enzyme is most active in E. Coli cells under anaerobic conditions?

a. Pyruvate carboxylase
b. Acetyl coenzyme A
c. Pyruvate dehydrogenase
d. Pyruvate decarboxylase

Answer 3

d. Pyruvate decarboxylase

Undergo ethanol fermentation, which involves pyruvate decarboxylase.

Question 4

Protein Z is a dimer whose subunits are connected by disulfide bonds. Which of the following is true regarding the denaturation of protein Z?

a. Heating protein Z will reversibly break down its tertiary structure; adding BME will reversibly break down its quaternary structure.
b. Heating protein Z will reversibly break down its tertiary structure; adding BME will irreversibly break down its quaternary structure.
c. Heating protein Z will irreversibly break down its tertiary structure; adding BME will reversibly break down its quaternary structure.
d. Heating protein Z will irreversibly break down its tertiary structure; adding BME will irreversibly break down its quaternary structure.

Answer 4

a. Heating protein Z will reversibly break down its tertiary structure; adding BME will reversibly break down its quaternary structure

Question 5

Elecrophoretic separation at pH 6 of a sample of polypeptide 1 (mw 100), polypeptide 2 (mw 200), and polypeptide 3 (mw 400) would result in which of the following? The isoelectric point for each polypeptide is at a pH of 6.

a. Polypeptide 2 would move the farthest
b. None would move
c. Polypeptide 1 would move the farthest
d. Polypeptide 3 would move the farthest

Answer 5

b. None would move