Regulation of Gene Expression 1

Question 1

Regulation of Gene Expression

Answer 1

Process by which the expression of genes is turned on and off at different times and under different conditions

Question 2

Transcriptional Regulation

Answer 2

• It is the most common and efficient
• Occur through transcriptional regulators, proteins that usually bind to DNA through helix-turn-helix motifs
• Can be negative(prevention) or Positive (activate)

Question 3

Post-transcriptional regulation

Answer 3

any regulation that occur after the gene been transcribed into mRNA
*the most common is translational regulation

Question 4

example of enzyme synthesis regulation?

Answer 4

lactose operon

Question 5

loci responsible lactose metabolism? (3)

Answer 5

-lacZ coding for β-galactosidase
_lacY coding for lactose permease
-lacA coding for transacetylase

Question 6

lacI is a _____ protein

Answer 6

represor

Question 7

LacZ cleave?

Answer 7

lactose to form glucose and galactose

Question 8

lacY allows?

Answer 8

the lactose into the cell

Question 9

lacA

Answer 9

function unknown

Question 10

lacI in absences of lactose.

Answer 10

in absences of lactose bind to the operator sequence (lacO) close to the promoter and prevent the binding of RNA polymerase, blocking the transcription of the structural genes

Question 11

lacI in presences of lactose

Answer 11

the inducer bind to the repressor change its conformation and no longer bind to the operator. Then RNA polymerase bind to the lacp and transcribe the lacZ, lacY and lacA genes

Question 12

lac operon that seem to abolish expression

Answer 12

NON INDUCIBLE

Question 13

lac operon that cause increased expression

Answer 13

CONSTITUTIVE