Electron transport chain and oxidative phosphorylation- Mcqs (set-1)

Q.1- All of the following except one are NAD⁺ requiring enzymes –

A. Acyl co A dehydrogenase

B. Glyceraldehyde-3-P dehydrogenase

C. Pyruvate dehydrogenase complex

D. Malate dehydrogenase

E. Lactate dehydrogenase

Q.2- Which one of the following enzymes catalyzes substrate-level phosphorylation in the TCA cycle

A. Malate dehydrogenase

B. Succinate Thiokinase

C. Succinate dehydrogenase

D. Alpha keto dehydrogenase complex

E. Isocitrate dehydrogenase

Q.3- The major metabolic consequence of perturbation of the electron transfer in mitochondria is which of the following?

A. Increased production of NADPH

B. Increased oxidation of NADH

C. Increased reduction of O₂ to H₂O

D. Decreased regeneration of NAD⁺

E. Decreased reduction of FAD

Q.4- An unskilled worker in a water garden/plant nursery was sent to sweep up a spill of a white powder in the storage shed. Later he was found with labored breathing and convulsions. On further examination, the white powder was identified as rotenone. Respiratory distress is induced on rotenone exposure because it inhibits the complex that catalyzes which of the following?

A. Electron transfer from NADH to coenzyme Q

B. Oxidation of coenzyme Q

C. Reduction of cytochrome c

D. Electron transfer from cytochrome c to cytochrome a1/a3

E. Electron transfer from cytochrome a1/a3 to oxygen

Q.5- Which of the following procedures best describes the emergency intervention for cyanide poisoning?

A. Decrease the partial pressure of oxygen

B. Treatment with nitrites to convert hemoglobin to methemoglobin.

C. Treatment with thiosulfate to form thiocyanate

D. Use of N-acetyl cysteine taken orally

E. Use of Antioxidants

Q.6- Inhibition of oxidative phosphorylation by cyanide ion leads to increases in which of the following?

A. Gluconeogenesis to provide more glucose for metabolism

B. Transport of ADP into the mitochondria

C. Utilization of fatty acids substrates to augment glucose utilization

D. Utilization of ketone bodies for energy generation

E. Lactic acid in the blood causing acidosis

Q.7- 27-year-old male with acute appendicitis undergoing a halothane inhaled anesthetic with acute onset of hyperthermia, tachypnea, respiratory acidosis, hyperkalemia, and family history of similar events. The tentative diagnosis is malignant hyperthermia (MH). Which of the following processes gets affected by Halothane?

A. Inhibition of NADH-Q oxidoreductase (Complex I)

B. Inhibition of Q-cytochrome c oxidoreductase (Complex III)

C. Inhibition of succinate Q reductase (Complex II)

D. Inhibition of ADP/ATP transporter

E. Uncoupling of oxidative phosphorylation

Q.8- The rate of respiration of mitochondria can be controlled by the availability of:

A. ADP

B. ATP

C. FMN

D.FAD

E. NAD ⁺

Q.9- Atractyloside inhibits oxidative phosphorylation by inhibiting:

A. NADH-Q oxidoreductase (Complex I)

B. Q-cytochrome c oxidoreductase (Complex III)

C. Succinate Q reductase (Complex II)

D. ADP/ATP transporter

E. Cytochrome a1-a3 oxidase

Q.10- The enzyme that catalyzes the direct transfer and incorporation of oxygen into a substrate molecule is known as:

A. Oxidase

B. Oxygenase

C. Peroxidase

D. Reductase

E. Hydratase

Key to Answers

1)-A, 2) -B, 3) – D, 4)-A, 5)-B, 6)-E, 7)-E, 8)-A, 9)-D, 10)-B