Catabolite repression in E. coli primarily demonstrates how:Question 3Answera.The presence of glucose enhances the utilization of lactose.b.Lactose can increase the cAMP levels in the cell.c.Glucose presence inhibits lactose metabolism.d.Glucose and lactose are metabolized simultaneously.

Which of the following best describes the role of catabolite repression in microbial metabolism?Question 18Answera.Increases the production of secondary metabolitesb.Prevents the synthesis of enzymes for secondary carbon sources when a preferred source is availablec.Activates the regulatory genes for enzyme productiond.Promotes the use of less preferred carbon sources

Lactose catabolism in E coliGroup of answer choicesIs maximal when lactose is present in the environmentIs normally a constitutive functionIs essential since it is the only sugar the bacterium can use as an energy sourceProduces lactose for the cell’s useIs controlled by a repressible operon

Ask StudybuddyThe activation of the lac operon requires a signaling molecule regulated by what monosaccharide? An increase in the synthesis of tryptophane regulated by Lac z A decrease in cAMP synthesis regulated by an increase in glucose An increase in cAMP regulated by a decrease of glucose A decrease in tryptophane that activates cAMP synthesis An increase in lactose that activates cAMP synthesis

In E. coli, transcription of the lac operon would be increased by:Group of answer choicesA missense mutation that disrupts the activity of the catabolite activator protein (CAP).A mutation in the lacI repressor gene that increases the affinity of the repressor for allolactose.A mutation in the lacI repressor gene that increases the affinity of the repressor for the lac operator.The presence of glucose in the growth medium.

The lac operon system, first described by Jacob and Monod, regulates lactose metabolism in . The is composed of a gene encoding a protein that normally keeps this operon in the position. Within the , the repressor binds to the , blocking transcription of structural genes needed for lactose metabolism. When is added to a cell's environment, it binds the repressor freeing the operator segment of the DNA. is now able to bind to the promoter, transcribing all three structural genes needed for lactose catabolism. When lactose again becomes depleted in the cell, the repressor binds to the operator blocking additional synthesis of enzymes from the .