Regulation Of Gene Expression In Prokaryotes

Front 1

Regulating gene expression saves ____

Back 1

Energy

Front 2

TRUE or FALSE: Gene regulation can be controlled at one point

Back 2

FALSE: gene regulation can be controlled at several points

Front 3

What are patterns of gene expression?

Back 3

1. Constitutive
2. Inducible
3. Repressible

Front 4

Constitutive

Back 4

- Expression always ON
- Gene products always needed
- House keeping genes

Front 5

Inducible

Back 5

- Default is OFF
- Turned on when needed
Eg: metabolize energy source

Front 6

Repressible

Back 6

- Default is ON
- turned off when not needed
- biosynthetic enzymes

Front 7

Efftor

Back 7

- Small molecule such as amino acids
- Interacts with REGULATOR protein to determine activity
- 2 types: INDUCERS and CO-REPRESSORS

Front 8

Lactose metabolism is controlled by genes encoded by the ____

Back 8

Iac operon

Front 9

Give a summary of the Jacob and Monod Iac operon model

Back 9

- Operator mutations affect only the genes downstream on the same DNA molecule
- Repressor gene product can control genes on a different DNA molecule
- Inducible system under negative control

Front 10

Catabolite repression of the Iac operon

Back 10

- Glucose is preferred energy source
- Lactose must first be metabolized to produce glucose
- Catabolite glucose represses Iac operon indirectly

Front 11

How does excess glucose over-ride lactose induction?

Back 11

By regulating cAMP levels

Front 12

trp operon

Back 12

Repressible system under negative control
5 enzymes control trp synthesis and trp operon shut off when trp available
when trp present it acts as the co-repressor

Front 13

Attenuation

Back 13

Second level of gene regulation different from repression/depression

TrP operson gene expression is reduced by addition of tryptophan in the absence of functional TRP repressor protein.

Front 14

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Back 14

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