Thinking of lactose operon regulation, what happens when E. coli is grown in medium with glucose...

Thinking of lactose operon regulation, what happens when E. coli is grown in medium with glucose and lactose?

Group of answer choices

neither Cap/cAMP activator nor LacI repressor are bound to a regulatory DNA sequence.

LacI repressor is bound to the OPERATOR sequence but Cap/cAMPactivator is not.

Cap/cAMP activator is bound to the CAP motif but LacI repressor is not.

both Cap/cAMP activator and LacI repressor are bound to the OPERATOR sequence.

Expert Solution

lactose is an inducer of the lac operon.

the lac operon is inhibited by the lac repressor binding to the lac operator, in the presence of an inducer lac repressor is inhibited by the inducer so lac repressor cannot bind to the operator, so if lactose is present lac repressor cannot bind to the lac operator.

glucose inhibits the expression of lac operon by catabolite repression. CAP is catabolite activator protein it binds to the CAP binding site and recruit RNA polymerase to the lac promoter and increases the rate of transcription, for CAP to bind to DNA it has to be bound with cAMP, glucose decreases the levels of cAMP in the cell so cAMP-CAP complex cannot form so CAP cannot bind to the CAP site if glucose is present in the cell.

so the answer is a) neither Cap/cAMP activator nor LacI repressor are bound to a regulatory DNA sequence.

gladiator answered 2 years ago

3. Explain what happens to the Lac operon when lactose is present and glucose is also...

3. Explain what happens to the Lac operon when lactose is present and glucose is also present. Then explain what happens when lactose is present but glucose is absent. In your answer, include all of the components of the Lac operon and the molecules involved in its regulation. What is the protein product of the Lac operon? Explain why this mechanism of control is adaptive.

E. coli cells are growing in a medium containing lactose but no glucose. Indicate whether each...

E. coli cells are growing in a medium containing lactose but no glucose. Indicate whether each of the following changes or conditions would increase, decrease, or not change the expression of the lac operon. For full credit, you must explain your answer. It may be helpful to draw a model depicting what is happening in each situation. (a) Addition of a high concentration of glucose (b) A mutation that prevents dissociation of the Lac repressor from the operator (c) A...

Briefly describe the Escherichia coli (E. coli) lac operon and its regulation.

A partial diploid strain of E. coli, grown in the presence of lactose and allolactose, does...

A partial diploid strain of E. coli, grown in the presence of lactose and allolactose, does NOT produce any functional beta galactosidase. What is the possible genotype of the cells? (genotypes on the chromosome / genotypes on the plasmid) lacI+ lacP+ lacOC lacZ+ / lacIS lacP+ lacO+ lacZ+ lacI+ lacP+ lacOC lacZ+ / lacI- lacP+ lacO+ lacZ+ lacI+ lacP+ lacOC lacZ+ / lacI+ lacP- lacO+ lacZ+ lacI+ lacP+ lacO+ lacZ+ / lacIS lacP+ lacO+ lacZ+

1. In E. coli cell is grown in the presence of high amounts of glucose. Which...

1. In E. coli cell is grown in the presence of high amounts of glucose. Which of the following is true? a. The cell will use lactose as a carbon source. b. The level of cyclic AMP in the cell will be low. c. The level of cyclic AMP in the cell will be high. d. Transcription of mRNA from the lac operon will be high e. The cell will die. 2. Enhancers are a. proteins located adjacent to promoters...

E. coli are able to break down lactose when present, and this is regulated by the...

E. coli are able to break down lactose when present, and this is regulated by the lac Operon. Describe the mechanisms for the positive and negative control of this operon, and briefly discuss the advantages of both forms of control for this operon.

1. Is thelacoperon a repressible or an inducible operon? What happens in the absence of lactose?...

1. Is thelacoperon a repressible or an inducible operon? What happens in the absence of lactose? What happens in the presence of lactose? Is the trp operon a repressible or an inducible operon? What happens in the absence of tryptophan? What happens in the presence of tryptophan?

Draw and/or discuss how the Lactose OPERON in bacteria. Include conditions such as no glucose, glucose...

Draw and/or discuss how the Lactose OPERON in bacteria. Include conditions such as no glucose, glucose and low lactose, lactose high and glucose low

In the E. coli trp operon, what would be the effect of a deletion in the...

In the E. coli trp operon, what would be the effect of a deletion in the region 2 sequence, which would prevent it from forming stable RNA hairpin structure with either regions 1 or 3? A) The Trp repressor could not bind to the operator and trp transcription will be high, even in the presence of high tryptophan concentration. B) Translation of the leader sequence could not be initiated. C) No effect on trp operon transcription. D) Transcription of the...

Assume you have a bacterium that possesses the lac operon. What happens when…… Glucose is present,...

Assume you have a bacterium that possesses the lac operon. What happens when…… Glucose is present, lactose is absent Describe what is happening to LacI in this situation. Feel free to use the diagram below to help sketch out what is happening and help you answer the question. Describe what is happening to CAP in this situation. Feel free to use the diagram below to help sketch out what is happening and help you answer the question. Are lacZ, lacY...

Question