Question

Please help me with this question and if you can explain why.

Which of the following statements are true for bacteria grown in the absence of glucose and absence of lactose? Select all that apply. High levels of cAMP CAP bound to CAP binding site Low or no levels of allolactose O High levels of lacZYA mRNA No transcription of lacZYA Lac repressor bound to operator CAP is not bound to binding site O High levels of allolactose Lac repressor not bound to operator

Answer 1

Ans:

The following statements are true for bacteria grown in the absence of glucose and absence of lactose:

- High levels of cAMP

- CAP bound to CAP binding site

- Low or no levels of allolactose

- No transcription of lacZYA

- Lac repressor bound to the operator

Explanation:

- In the absence of glucose and lactose, no transcription of lac operon occurs.

- cAMP levels are high because glucose levels are low, so CAP is active and will be bound to the DNA.

- However, the lac repressor will also be bound to the operator (due to the absence of the allolactose), acting as a roadblock to RNA polymerase and preventing transcription.