Question

Which of the following statements about regulation of the lac operon is true? Select all that...

Which of the following statements about regulation of the lac operon is true? Select all that apply.

Group of answer choices

When glucose is present but lactose is absent, gene expression is activated at the lac operon.

The presence of glucose in the growth medium does not affect the level of gene expression activated by the presence of lactose.

The lac repressor can dissociate from the operator in the presence of glucose.

Gene expression is high when the lac repressor is not bound to the operator and glucose is unavailable.

Gene expression is high when the lac repressor is not bound to the operator and glucose and lactose are available.

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Answer #1

True statements:

1. The lac repressor can dissociate from the operator in the presence of glucose.

2. Gene expression is high when the lac repressor is not bound to the operator and glucose is unavailable.

False statement :

1. When glucose is present but lactose is absent, gene expression is activated at the lac operon. (No, gene activation requires lactose).

2 .The presence of glucose in the growth medium does not affect the level of gene expression activated by the presence of lactose.(present of glucose decreases the gene expression of lactose, since there will be no cAMP, which up regulate the gene expression)

3. Gene expression is high when the lac repressor is not bound to the operator and glucose and lactose are available.(no gene expression will be done, if there is no lactose).

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