Free Metabolism and Bioenergetics MCQs with Answers

• A. 6alactosemia
• B. Alkaptonuria
• C. Homocystinuria
• D. Phenyl ketonuria

Explanation: Phenylketonuria, alkaptonuria, and homocystinuria result from inherited defects in amino-acid metabolism.

• A. It is a tripetide
• B. It converts hemoglobin to methemoglobin
• C. It conjugates xenobiotics
• D. It scavenges free radicals and superoxide ions

Explanation: Glutathione is a tripeptide that detoxifies xenobiotics and protects cells by reducing reactive oxygen species.

• A. Brain
• B. Kidney
• C. Liver
• D. Intestine

Explanation: Urea is formed mainly in the liver through the urea cycle, which converts toxic ammonia into a less toxic compound for renal excretion.

• A. Urease
• B. Uricase
• C. Glutaminase
• D. Arginase

Explanation: Arginase catalyses the final urea-cycle reaction, splitting arginine into urea and ornithine.

• A. Fumarate
• B. Succinate
• C. Ornithine
• D. Aspartate

Explanation: Argininosuccinate is cleaved in the urea cycle to produce arginine and fumarate.

• A. Parahydroxy phenyl pyruvate Hydroxylase
• B. Homogentisate oxidase
• C. Tyrosine transaminase
• D. Tyrosine oxidase

Explanation: Alkaptonuria results from deficiency of homogentisate oxidase in tyrosine degradation.

• A. It is required for the process of transmination
• B. It is co-factor in oxidative reduction
• C. It is co-enzyme for transketolase in pentose phosphate pathway
• D. It is co-enzyme for pyruvate dehydrogenase

Explanation: Thiamine pyrophosphate is a coenzyme for pyruvate dehydrogenase, allowing pyruvate to enter acetyl-CoA formation and the TCA cycle for…

• A. Pyruvate to acetyl CoA
• B. Citrate to alpha ketoglutarate
• C. Succinyl CoA to fumarate
• D. None of the above

Explanation: Thiamine pyrophosphate, the active form of vitamin B1, is required by pyruvate dehydrogenase for conversion of pyruvate to acetyl-CoA.