Question 1

Which of the following statements best describes the difference between eukaryotic and prokaryotic cells?

Accepted Answer

Eukaryotic cells have membrane-bound organelles and a nucleus, while prokaryotic cells lack both.

Question 2

Which intermolecular force is primarily responsible for the high boiling point of water?

Accepted Answer

Hydrogen bonding

Question 3

A solution contains 0.01 M acetic acid ($$\mathrm{p}K_a = 4.76). $$What is the pH of the solution if the concentration of acetate ion equals the concentration of acetic acid?

Accepted Answer

$$\mathrm{pH} = 4.76$$

Question 4

Which amino acid is classified as a basic amino acid and contains a guanidinium group?

Accepted Answer

Arginine

Question 5

A peptide is formed from the condensation of two amino acids. Which functional groups are involved in this reaction?

Accepted Answer

Amino group and carboxyl group

Question 6

Which of the following best describes the secondary structure of proteins?

Accepted Answer

The folding of the polypeptide into alpha-helices and beta-sheets stabilized by hydrogen bonds

Question 7

Which enzyme class is responsible for catalyzing the transfer of a phosphate group from ATP to a substrate?

Accepted Answer

Transferases

Question 8

In Michaelis-Menten kinetics, what does $$K_m$$ represent?

Accepted Answer

The substrate concentration at which the reaction velocity is half of $$V_{max}$$

Question 9

A competitive inhibitor affects enzyme kinetics by:

Accepted Answer

Increasing $$K_m$$ without affecting $$V_{max}$$

Question 10

Which of the following statements about zymogens is correct?

Accepted Answer

Zymogens are inactive precursors that are activated by proteolytic cleavage.

Question 11

Which carbohydrate is an epimer of glucose at the C-2 position?

Accepted Answer

Mannose

Question 12

Which of the following best describes the difference between aldoses and ketoses?

Accepted Answer

Aldoses contain an aldehyde group, while ketoses contain a ketone group.

Question 13

Which of the following lipids is a major component of biological membranes and contains a glycerol backbone, two fatty acids, and a phosphate group?

Accepted Answer

Phosphatidic acid

Question 14

Which factor increases the melting point of a fatty acid?

Accepted Answer

Increasing the chain length and decreasing unsaturation

Question 15

Which of the following is true regarding the transport of molecules across biological membranes?

Accepted Answer

Active transport moves molecules against their concentration gradient and requires energy.

Question 16

Which molecule acts as a second messenger in cell signaling and is produced from ATP by adenylyl cyclase?

Accepted Answer

cAMP

Question 17

A patient is diagnosed with a deficiency in a reducing agent required for the conversion of methemoglobin to hemoglobin. Which molecule is most likely deficient?

Accepted Answer

NADH

Question 18

Given the following reaction: $$\mathrm{Fe}^{2+} \rightarrow \mathrm{Fe}^{3+} + e$$^{-}$$, which species is being oxidized?

Accepted Answer

$$\mathrm{Fe}^{2+}$$

Question 19

Which of the following best describes the role of lectins in biological systems?

Accepted Answer

Lectins are proteins that bind specifically to carbohydrates and mediate cell-cell recognition.

CHM 330 Exam 1: Comprehensive Biochemistry Study Guide

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