Question 1

Which of the following best describes the induced fit model of enzyme-substrate binding?

Accepted Answer

The enzyme's active site undergoes a conformational change to better accommodate the substrate upon binding.

Question 2

Which enzyme class does a reaction that transfers a phosphate group from ATP to glucose belong to?

Accepted Answer

Transferase

Question 3

Apoenzyme refers to:

Accepted Answer

The protein portion of an enzyme without its cofactor

Question 4

Given the Michaelis-Menten equation $$v = \frac{V_{max}[S]}{K_m + [S]}$$, what happens to $$V_{max}$$ and $$K_m in $$the presence of a competitive inhibitor?

Accepted Answer

$$V_{max}$$ remains unchanged, $$K_m$$ increases

Question 5

Which amino acid is most likely to participate in acid/base catalysis in an enzyme's active site?

Accepted Answer

Histidine

Question 6

A Lineweaver-Burk plot is a double reciprocal plot of enzyme kinetics. Which equation represents this plot?

Accepted Answer

$$\frac{1}{v} = \frac{K_m}{V_{max}} \cdot \frac{1}{[S]} + \frac{1}{V_{max}}$$

Question 7

Which of the following best describes the effect of allosteric modulators on enzyme activity?

Accepted Answer

They bind to a site other than the active site and alter the enzyme's activity by changing its conformation.

Question 8

Hemoglobin exhibits cooperative binding of oxygen. Which curve best represents this behavior?

Accepted Answer

A sigmoidal curve

Question 9

Which of the following factors will decrease hemoglobin's affinity for oxygen at high altitude?

Accepted Answer

Increased BPG concentration

Question 10

Which statement about the structure of cellulose is correct?

Accepted Answer

Cellulose is composed of glucose units linked by $$\beta-1$$,4-glycosidic bonds.

Question 11

A sugar with four chiral centers will have how many stereoisomers?

Accepted Answer

16

Question 12

Which of the following is a reducing disaccharide?

Accepted Answer

Lactose

Question 13

Which term describes two sugars that differ only at one chiral center?

Accepted Answer

Epimers

Question 14

Which of the following statements about the catalytic mechanism of chymotrypsin is correct?

Accepted Answer

Chymotrypsin utilizes both acid/base and covalent catalysis.

Question 15

Which of the following best describes the effect of a noncompetitive inhibitor on enzyme kinetics?

Accepted Answer

$$V_{max}$$ decreases, $$K_m$$ remains unchanged

Question 16

Which of the following is true about the conversion of D-glucose to L-glucose?

Accepted Answer

All chiral centers are inverted in L-glucose compared to D-glucose.

Question 17

Which of the following is a characteristic of glycogen compared to amylopectin?

Accepted Answer

Glycogen has more frequent $$\alpha-1$$,6-branch points.

Question 18

Which of the following statements about the heme group in hemoglobin is correct?

Accepted Answer

The central iron ion is coordinated by four nitrogen atoms of the porphyrin ring and two additional ligands.

Question 19

Which of the following best describes the effect of proteolytic cleavage on zymogens?

Accepted Answer

It irreversibly activates the enzyme by removing a peptide segment.

Question 20

Which of the following is an example of a glycosaminoglycan?

Accepted Answer

Heparin

CHEM 161 Exam 2 Study Guide: Enzymes, Hemoglobin, and Carbohydrates

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