Regulation of Gene Expression

Question 1

Gene Expression

Answer 1

Genes (operons) transcription can be turned on off based on environmental and internal cues

Allows for cell specialization—>unique structure of a cell that allows it to carry out functions

Question 2

Operons

Answer 2

A group of genes that can be turned on or off

3 parts
1. Promoter: where RNA polymerase can attach
2. Operator: the on and off switch
3. Genes: code for related enzymes in pathway

Types of operons

Repressible (on to off): transcription is usually on, but can be repressed

Inducible (off to on): transcription is usually off, but can be induced

Question 3

trp operon

Answer 3

-Controls synthesis of tryptophan in bacteria
-Transcription is active
-Can be turned off by yep repressor
-Allosteric enzyme is only active when tryptophan binds

Too much tryptophan—>More likely to bind ti repressor—>Repressor active (no transcription)

*visual in notes

Question 4

lac operon

Answer 4

-controls synthesis of lactase
-Transcription is off
-A lac repressor is found to operator (allosterically active)

Inducer: allolactose (turns on transcription, binds to repressor)

*visual in notes