Question

When an LDL particle is taken up by the cell, what impact will this have on the regulation of de novo cholesterol synthesis?
A. Transcription of HMG-CoA reductase will be elevated
B. SREBP will be inhibited by Insig in the endoplasmic reticulum
C. HMG-CoA reductase will be dephosphorylated
D. SREBP will be active in the nucleus

Answer 1

Answer:

C. HMG-CoA reductase will be dephosphorylated

Explanation:

When a low density lipoprotein particle is taken up by the cell, the impact it will have on the regulation of de novo cholesterol synthesis will be HMG-CoA reductase being dephosphorylated.

HMG-CoA( 3-hydroxy-3-methyl-glutaryl-CoA reductase) is an enzyme which aids the synthesis of lipids. When the lipids are produced and taken up by the cells then the effect of the synthesis stops to avoid excess synthesis and to allow for the action of enzymes which will act ok them in the cells . This is why it leads to a dephosphorylation of the enzyme which stops the action.