Molecular Genetics - Regulation of Gene Expression

Question 1

Constitutive Genes

Answer 1

always active

Question 2

Gene regulation happens most often during

Answer 2

initiation of transcription

Question 3

What is an operon

Answer 3

a cluster of genes under the control of one promoter

Question 4

What is in the coding region

Answer 4

promoter and operator

Question 5

in an absence of lactose

Answer 5

the repressor binds to the operator so that RNA polymerase cannot perform transcription

Question 6

when lactose is present

Answer 6

lactose is converted to allolactose which binds to the repressor and changes its conformation so that it can no longer bind to the operator. RNA polymerase can now transcribe so that the lac genes are formed.

Question 7

Prokaryotes use trp to regulate the production of

Answer 7

tryptophan

Question 8

In the absence of tryptophan

Answer 8

repressor is in an inactive state and cannot bind

Question 9

In the presence of tryptophan

Answer 9

it activates the repressor and blocks transcription