Question

Assume there is a nonsense mutation in the coding sequence for lacZ. The bacteria cell is grown in high lactose and high. glucose. Circle ALL of the correct answers when ONLY studying Inducer Exclusion (IE) for the lac operon. Repressor unable to bind to operator so transcription proceeds slowly glucose binds to gal perm and inactivates the protein via post-translational control Both lactose and glucose are inside the cell Glucose binds gal perm and inactivates the protein via translational control Repressor binds to the operator and then has P.P with RNA Pol to stop transcription Only glucose is inside the cell Glucose binds gal perm and inactivates the protein via transcriptional control Only lactose is inside the cell Assume a bacteria cell that has a lacl-mutation is living in high lactose no glucose conditions. Circle ALL of the correct answers when ONLY studying positive regulation of the lac operon.

a. CAP-CAMP binds CBE
b. There is fast transcription of the lac operon
c. AC is inhibited
d. AC is activated
e. cAMP unable to bind CAP
f. CAP is in wrong shape so can't bind CBE
g. CAMP binds CAP
h. There is slow transcription of the fac operon

Answer 1

In the presence of high lactose and high glucose, the bacteria's lac operon will be affected by Inducer Exclusion where glucose inactivates gal perm through post-translational control. When only lactose is present and lacl- mutation occurs, cAMP binds CAP, resulting in fast transcription of the lac operon as the cAMP-CAP complex binds to CBE.

Step-by-step explanation:

The lac operon is an inducer operon in E. coli that is involved in the metabolism of lactose. It is regulated by several factors including the presence of glucose and lactose in the cell's environment. Regarding Inducer Exclusion (IE), when both glucose and lactose are present, glucose will bind to the gal permease (gal perm) and inactivate it through post-translational modification, not via transcriptional or translational control. In a cell with an lacl- mutation living in high lactose and no glucose conditions, the cAMP levels rise, allowing cAMP to bind to CAP, activating it, and leading to fast transcription of the lac operon as the CAP-cAMP complex binds to the catabolite binding element (CBE).