Bio Topic #10 Gene Regulation

Gene regulation

Ability of a cell to control the expression of its genes

main advantage of gene regulation

conserve energy

Explain how gene regulation allows cells to specialize

Different types of cells express different types of genes

Gene regulation most commonly occurs at which level of gene expression?

Transcription

Which transcription factor inhibits transcription?

Repressor

Which transcription factor promotes transcription?

Activator

which molecule controls the activity of a transcription factor

effector

operon

set of 2 or more genes controlled by 1 promoter

Function of the genes in the lac operon

allow bacteria to use lactose as an energy source

the lac operon is (transcribed) when_____ is available in the cell and___ is unavailable

Lactose, Glucose

Activator:

• activity is dependent on glucose levels in the cell

• Binds to CAP site

• Ability to bind CAP site is controlled by cAMP

Repressor:

• Activity is dependent on lactose levels in the cell

• binds to operator

• ability to bind operator is controlled by allolactose

When lactose is present in the cell does the repressor bind to the operator? Is transcription of the operon turned on or off?

NO, ON

When lactose is Absent in the cell does the repressor bind to the operator? Is transcription of the operon turned on or off?

YES, OFF

cAMP is only produced in the cell when glucose is…

absent

Which form of CAP activator binds to the CAP site to activate transcription?

CAP activator bound to cAMP

2 conditions must be met for the lac operon to be turned on

1. CAP activator is bound

2. Repressor is NOT bound