Gene regulation in prokaryotes Flashcards Preview

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Flashcards in Gene regulation in prokaryotes Deck (19):
1

Constitutively expressed genes

expressed in most cells (DNA replication, transcription and translation)

2

Regulated genes

are inducible or repressible

3

Operon

genes whose products are involved in the same metabolic pathway

4

Components of operon

repressor
effector molecule
operator
promoter
structural genes

5

repressor

represses the expression of structural genes

6

effector molecule

regualtes binding of the operon to the operator sequence

7

promoter

controls transcription

8

structural genes

Z, Y, A required for lactose metabolism

9

regulatory gene

lac l codes for lac operon repressor protein

10

operator

lac O - DNA binding site for the repressor protein

11

lac Y

lactose permease - transport of lactose from the environment

12

lac Z

B-galactosidase - cleave lactose into glucose and galactose - converts lactose to allolactose

13

lac A

function unknown (maybe toxicity)

14

lac l

encodes lac repressor

15

lac O

lac operator -controls the lac operon through repressor binding

16

allolactose

binds the lac repressor inducing a conformational change

17

cAMP

regulates lac operon activity via binding to CAP (catabolite activator protein) that binds to the lac operator

18

cAMP/CAP

helps orient RNA polymerase and exerts positive control over transcription of the lac operon

19

feedback inhibition

the final product of a biosynthetic pathway inhibits the activity of the first enzyme in the pathway shutting it off