Question 1

Which of the following amino acids is classified as polar and uncharged at physiological pH?

Accepted Answer

Serine

Question 2

During peptide bond formation, which type of reaction occurs between two amino acids?

Accepted Answer

Condensation reaction

Question 3

A polypeptide contains the following amino acids: Glu, Lys, and Asp. At neutral pH, what is the net charge of the polypeptide?

Accepted Answer

$-1$

Question 4

Which secondary structure is stabilized primarily by hydrogen bonds between backbone atoms?

Accepted Answer

Alpha helix

Question 5

Which of the following statements about globular proteins is TRUE?

Accepted Answer

They typically have hydrophilic residues exposed to the solvent.

Question 6

A protein is denatured by heat. Which property is most likely to decrease as a result?

Accepted Answer

Solubility in water

Question 7

Which protein purification method separates proteins based on their size?

Accepted Answer

Size exclusion chromatography

Question 8

Hemoglobin exhibits cooperative binding of oxygen. Which of the following best describes this phenomenon?

Accepted Answer

Binding of one oxygen molecule increases the affinity for subsequent oxygen molecules.

Question 9

The Bohr effect describes how changes in pH affect hemoglobin's oxygen binding. What happens to oxygen affinity as pH decreases?

Accepted Answer

Oxygen affinity decreases

Question 10

Which structural protein is primarily responsible for the formation of microtubules?

Accepted Answer

Tubulin

Question 11

Which motor protein is involved in muscle contraction?

Accepted Answer

Myosin

Question 12

Which chemical catalytic mechanism involves the transfer of a proton?

Accepted Answer

Acid-base catalysis

Question 13

The catalytic triad is a key feature of which enzyme class?

Accepted Answer

Proteases

Question 14

Which cofactor is required for the function of hemoglobin?

Accepted Answer

Heme

Question 15

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

Accepted Answer

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

Question 16

Which type of enzyme inhibition can be overcome by increasing substrate concentration?

Accepted Answer

Competitive inhibition

Question 17

A Lineweaver-Burk plot is a double reciprocal plot of enzyme kinetics. What is plotted on the y-axis?

Accepted Answer

$1/v$

Question 18

Which of the following statements about allosteric effectors is TRUE?

Accepted Answer

They can increase or decrease enzyme activity by binding at a site other than the active site.

Question 19

Which of the following is a reason for regulating enzyme activity in cells?

Accepted Answer

To maintain metabolic balance and respond to environmental changes

Question 20

Given the Michaelis-Menten equation $v = \frac{V_{max}[S]}{K_m + [S]}$, what happens to the reaction rate $v$ when $[S] \gg K_m$?

Accepted Answer

The reaction rate approaches $V_{max}$.

Biochemistry Study Guide: Proteins, Enzymes, and Ligand Binding

Study Guide - Practice Questions