Biochemistry : Lipid Catabolism Intermediates

Study concepts, example questions & explanations for Biochemistry

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Example Questions

Example Question #23 : Lipid Catabolism

Phosphatidate is an intermediate in the synthesis of __________.

Possible Answers:

sphingolipids

triacylglycerols and glycerophospholipids

Sterols

glycerophospholipids

triacylglycerols

Correct answer:

triacylglycerols and glycerophospholipids

Explanation:

Phosphatidate is an intermediate in the synthesis of triacylglycerols and glycerophospholipids. This is simply because phosphatidate is the primary intermediate in lipid metabolism (which occurs in the synthesis of triacylglycerols and glycerophospholipids). More specifically, this intermediate is acylated to triacylglycerol through a fatty acid chain, and results in a glycerophospholipid product.

Example Question #2 : Lipid Catabolism Intermediates

Which product of the oxidation of fatty acids is an important intermediate in the citric acid cycle?

Possible Answers:

Fatty acyl-CoA

Succinyl-CoA

A fatty acyl-CoA two carbon atoms shorter in length

FADH₂

Acetyl-CoA

Correct answer:

Acetyl-CoA

Explanation:

The correct answer is "Acetyl-CoA." The oxidation of fatty acids is activated by attachment to Coenzyme A to form fatty acyl-CoA, and the oxidation results in a shorter fatty acyl-CoA and acetyl-CoA. The acyl-CoA is oxidized in the citric acid cycle, where it is an important intermediate. Succinyl-CoA is also an intermediate in the citric acid cycle but is not a direct product of fatty acid oxidation. The shorter fatty acyl-CoA is oxidized further into FADH₂, but not as part of the citric acid cycle.

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