Question 1

Which of the following best explains the cooperative binding of oxygen to hemoglobin?

Accepted Answer

Oxygen binding to one subunit increases the affinity of the remaining subunits for oxygen due to a conformational change.

Question 2

A patient with chronic hypoxia is treated with a drug that increases 2,3-BPG levels in red blood cells. What is the expected effect on hemoglobin's oxygen affinity?

Accepted Answer

Hemoglobin's oxygen affinity will decrease, facilitating oxygen release to tissues.

Question 3

Which region of an antibody determines its antigen specificity?

Accepted Answer

The variable region of both heavy and light chains

Question 4

Why are antibodies generally not suitable for treating most viral diseases?

Accepted Answer

Viruses mutate rapidly, altering their antigens and evading antibody recognition.

Question 5

Which of the following best describes the principle behind the ELISA technique?

Accepted Answer

Detection of specific antigens or antibodies using enzyme-linked secondary antibodies and a colorimetric reaction

Question 6

A mutation replaces a serine residue with alanine in the active site of an enzyme. Which property is most likely to be affected?

Accepted Answer

The enzyme's ability to form hydrogen bonds with the substrate

Question 7

Given the Michaelis–Menten equation $v = \frac{V_{max}[S]}{K_M + [S]}$, what does a low $K_M$ value indicate about an enzyme?

Accepted Answer

The enzyme has a high affinity for its substrate.

Question 8

Which of the following best describes the difference between competitive and noncompetitive enzyme inhibition?

Accepted Answer

Competitive inhibitors bind to the active site, increasing $K_M$ but not affecting $V_{max}$; noncompetitive inhibitors bind elsewhere, decreasing $V_{max}$ but not affecting $K_M$.

Question 9

A Lineweaver–Burk plot of an enzyme-catalyzed reaction yields a straight line with a y-intercept of $0.2$ min/μmol and an x-intercept of $-0.05$ mM$^{-1}$. What are the values of $V_{max}$ and $K_M$?

Accepted Answer

$V_{max} = 5$ μmol/min, $K_M = 0.25$ mM

Question 10

Which of the following is a common feature of all carbohydrates?

Accepted Answer

They all have the general formula $C_n(H_2O)_n$.

Question 11

Which amino acid is commonly involved in the formation of N-linked glycosidic bonds in glycoproteins?

Accepted Answer

Asparagine

Question 12

Which of the following is the primary storage form of carbohydrates in animals?

Accepted Answer

Glycogen

Question 13

A patient is diagnosed with a defect in aquaporin channels. Which physiological process is most likely to be impaired?

Accepted Answer

Rapid water transport across cell membranes

Question 14

Which of the following best describes the function of lipid rafts in biological membranes?

Accepted Answer

They organize membrane proteins and lipids for cell signaling and trafficking.

Question 15

Which of the following transport systems requires direct energy input from ATP hydrolysis?

Accepted Answer

Primary active transport

Question 16

Which of the following is NOT a major class of membrane lipids?

Accepted Answer

Triacylglycerols

Question 17

A patient with hyperventilation is administered a treatment that shifts the hemoglobin-oxygen dissociation curve to the right. What is the physiological benefit of this shift?

Accepted Answer

Enhanced oxygen release to peripheral tissues

Question 18

Which of the following best explains why Western blotting is used after SDS-PAGE in protein analysis?

Accepted Answer

To transfer proteins to a membrane and detect specific proteins using antibodies

Question 19

Which of the following statements about the major bond in polysaccharides is correct?

Accepted Answer

Polysaccharides are linked by glycosidic bonds.

Biochemistry Study Guide: Hemoglobin, Enzymes, Carbohydrates, and Membranes

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