Lipid metabolism: alcoholic fatty liver: practice question

A Biochemistry question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Biochemistry · Lipid metabolism: alcoholic fatty liver

Sample item

A chronic alcohol user has an enlarged, fatty liver on ultrasound. Which metabolic change from ethanol oxidation contributes most directly to triglyceride accumulation?

AA high NADH/NAD+ ratio that inhibits fatty acid oxidationBEnhanced hepatic export of VLDLCA high NAD+/NADH ratio that stimulates beta-oxidationDIncreased carnitine palmitoyltransferase I activity

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. A high NADH/NAD+ ratio that inhibits fatty acid oxidation

Ethanol oxidation by alcohol and aldehyde dehydrogenase generates large amounts of NADH. This high NADH/NAD+ ratio slows beta-oxidation and the TCA cycle, diverts fatty acids to triglyceride synthesis, and favours glycerol-3-phosphate formation, so fat accumulates in hepatocytes.

Option by option

A. A high NADH/NAD+ ratio that inhibits fatty acid oxidation (correct)
Correct. Excess NADH suppresses fatty acid oxidation and favours triglyceride synthesis.
B. Enhanced hepatic export of VLDL
Enhanced VLDL export would reduce hepatic fat and is not the main change in alcoholic steatosis.
C. A high NAD+/NADH ratio that stimulates beta-oxidation
Ethanol raises NADH, not NAD+, so beta-oxidation is suppressed rather than stimulated.
D. Increased carnitine palmitoyltransferase I activity
Increased CPT-I activity would raise fatty acid oxidation and would not explain fat accumulation.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Biochemistry question

What is the answer to this Biochemistry question?

The best answer is A, A high NADH/NAD+ ratio that inhibits fatty acid oxidation. Ethanol oxidation by alcohol and aldehyde dehydrogenase generates large amounts of NADH.

Why is "Enhanced hepatic export of VLDL" not the answer?

Enhanced VLDL export would reduce hepatic fat and is not the main change in alcoholic steatosis.

Why is "A high NAD+/NADH ratio that stimulates beta-oxidation" not the answer?

Ethanol raises NADH, not NAD+, so beta-oxidation is suppressed rather than stimulated.

Why is "Increased carnitine palmitoyltransferase I activity" not the answer?

Increased CPT-I activity would raise fatty acid oxidation and would not explain fat accumulation.

What concept does this question test?

It tests Lipid metabolism: alcoholic fatty liver in Biochemistry. This high NADH/NAD+ ratio slows beta-oxidation and the TCA cycle, diverts fatty acids to triglyceride synthesis, and favours glycerol-3-phosphate formation, so fat accumulates in hepatocytes.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Lipid metabolism: alcoholic fatty liver?

Build one table of enzyme deficiency, disease, inheritance and key finding, then revise it by spaced recall. Then use the flashcards and the other Biochemistry questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.