Question 1

Which property of water is most critical for maintaining protein structure in living systems?

Accepted Answer

Its capacity for hydrogen bonding

Question 2

A buffer system in blood helps maintain pH homeostasis. If a patient has metabolic acidosis, which buffer equation best describes the primary system involved?

Accepted Answer

$$\mathrm{CO_2$ + H_2O \rightleftharpoons H_2CO_3 \rightleftharpoons $$HCO_3$$^- + H^+}$$

Question 3

Which amino acid would most likely be found at the active site of an enzyme catalyzing a phosphorylation reaction?

Accepted Answer

Serine

Question 4

A mutation causes the substitution of a nonpolar amino acid for a charged one in the interior of a protein. What is the most likely effect?

Accepted Answer

Disruption of protein folding and stability

Question 5

Which equation correctly represents the relationship between Gibbs free energy, enthalpy, and entropy?

Accepted Answer

$$\Delta G = \Delta H - T\Delta S$$

Question 6

During anaerobic glycolysis in red blood cells, which molecule is produced to regenerate NAD$$^+$$?

Accepted Answer

Lactate

Question 7

Which process is directly inhibited by the drug thalidomide, as discussed in the context of protein structure?

Accepted Answer

Protein folding

Question 8

A patient with diabetes has impaired glucose transport into cells. Which protein is most likely defective?

Accepted Answer

GLUT4

Question 9

Which metabolic pathway is responsible for the conversion of pyruvate to glucose during fasting?

Accepted Answer

Gluconeogenesis

Question 10

Which statement best describes the role of the Fed/Fast cycle in human metabolism?

Accepted Answer

It regulates the switch between carbohydrate and lipid metabolism based on nutrient availability.

Question 11

Which of the following is a major function of the electron transport chain in mitochondria?

Accepted Answer

Generation of a proton gradient for ATP synthesis

Question 12

A patient presents with symptoms of hemoglobinopathy. Which aspect of hemoglobin function is most likely affected?

Accepted Answer

Oxygen binding and release

Question 13

Which equation describes the Michaelis-Menten relationship for enzyme kinetics?

Accepted Answer

$$v = \dfrac{V_{max}[S]}{K_m + [S]}$$

Question 14

Which vitamin is essential for the carboxylation reactions in gluconeogenesis?

Accepted Answer

Biotin

Question 15

Which process is most directly affected in a patient with a deficiency in carnitine?

Accepted Answer

Fatty acid transport into mitochondria

Question 16

Which of the following best explains why ATP is considered the universal energy currency in cells?

Accepted Answer

Its hydrolysis releases energy that can be coupled to endergonic reactions.

Question 17

A patient is given a drug that inhibits the enzyme pyruvate dehydrogenase. Which metabolic pathway will be most directly affected?

Accepted Answer

Conversion of pyruvate to acetyl-CoA

Question 18

Which of the following is a unique feature of lipid metabolism compared to carbohydrate metabolism?

Accepted Answer

Production of ketone bodies during fasting

Question 19

Which statement best describes the role of hormones in metabolic integration?

Accepted Answer

Hormones coordinate the activity of metabolic pathways in response to physiological needs.

Question 20

A patient with a genetic defect in the urea cycle will most likely present with which clinical symptom?

Accepted Answer

Hyperammonemia

Biochemistry 545/645: Protein Structure, Nutrition, and Metabolism – Study Guide

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