The Following Statements About Retinol Are True EXCEPT

question 72

Multiple Choice

The following statements about retinol are true EXCEPT:

• A) It is toxic at high dosages.
• B) It has hormone-like activity in that it has cellular receptors which act as transcription enhancers.
• C) It can be oxidized in the body to retinoic acid.
• D) It is an intermediate in the isomerization of trans-retinal to 11-cis-retinal in the visual cycle of the eye.
• E) It cannot be stored for long periods in the body.

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Definitions:

Operon

A functional unit of DNA containing a group of genes controlled by a single promoter, used by prokaryotes to regulate gene expression efficiently.

Structural Genes

Genes that code for proteins which serve as building blocks for cells and tissues or operate in metabolic or physiological processes.

Regulatory Sequences

Segments of DNA that are involved in controlling the activity of genes, including when, where, and how much of a gene product is made.

Constitutive

Expressed continuously under normal physiological conditions, not subject to regulation by environmental conditions.