7/28/2019 PP Gene Regulation

1/27

GENE REGULATION

7/28/2019 PP Gene Regulation

2/27

HOWDOESACELLKNOW.

which gene to EXPRESS

&

which gene should staySILENT?

7/28/2019 PP Gene Regulation

3/27

GENE REGULATION

When a gene is EXPRESSED, it is

transcribed into mRNA.

When a gene is SILEN T, it is NOT

transcribed.

EXPRESSED GENE = TRANSCRIBED

SILENT GENE = NOT TRANSCRIBED

7/28/2019 PP Gene Regulation

4/27

EXAMPLE: Blood sugar

Pancreas Insulin

Somatic cells

Cellular

respirationATP

Kinetic energy

7/28/2019 PP Gene Regulation

5/27

QUESTIONWHYTHEPANCREASWHYNOTYOUR

LUNGS???

7/28/2019 PP Gene Regulation

6/27

GENE REGULATION

Why would a cell NOT want to

express a gene?

Wastes energy & materialsATP

7/28/2019 PP Gene Regulation

7/27

GENE REGULATION

Cells regulate what genes are

expressed based on what protein

the cell NEEDS.

7/28/2019 PP Gene Regulation

8/27

WHEREDOES GENE REGULATION

OCCUR?

Most regulation occurs

at the DNA to RNA

steptranscription!

Why?

Conserves the most

energy!

7/28/2019 PP Gene Regulation

9/27

LETSLOOKATABASICEXAMPLEOFGENEREGULATION:

E.COLIINOURGUTFEEDOFFWHATWEPUTINTOOUR

DIGESTIVESYSTEM

Proteins amino acids

Carbohydrates sugars

7/28/2019 PP Gene Regulation

10/27

PROKARYOTIC GENE REGULATION

In prokaryotes, genes are organized into operons.

What is an operon?

A group of genes that code for the same function, and

are regulated by the same promoter and operator.

One promoter/operator controls the expression of

multiple genes.

7/28/2019 PP Gene Regulation

11/27

LETSLOOKATABASICEXAMPLEOFGENEREGULATION:

E.COLIINOURGUTFEEDOFFWHATWEPUTINTOOUR

DIGESTIVESYSTEM

Proteins amino acids

Carbohydrates sugars

7/28/2019 PP Gene Regulation

12/27

PROMOTERS

What is a promoter? Specific DNA base pair sequence that provides a

binding site for RNA polymerase.

Promotes or allows transcription to occur

7/28/2019 PP Gene Regulation

13/27

LETSLOOKATABASICEXAMPLE:

E.COLIINOURGUTFEEDOFFWHATWEPUTINTO

OURDIGESTIVESYSTEM

7/28/2019 PP Gene Regulation

14/27

STARTAND STOP BASE PAIR

SEQUENCES

What do they do? Control where transcription starts and stops.

If changed (mutated), transcription is altered.

AUGUAA

UAG

UGA

7/28/2019 PP Gene Regulation

15/27

LETSLOOKATABASICEXAMPLE:

E.COLIINOURGUTFEEDOFFWHATWEPUTINTO

OURDIGESTIVESYSTEM

7/28/2019 PP Gene Regulation

16/27

OPERATORS

What is an operator?

Like an on/off switch.

Proteins bind to the operator to regulate

transcription.

7/28/2019 PP Gene Regulation

17/27

LETSLOOKATABASICEXAMPLE:

E.COLIINOURGUTFEEDOFFWHATWEPUTINTO

OURDIGESTIVESYSTEM

7/28/2019 PP Gene Regulation

18/27

REPRESSOR PROTEINS What is a repressor protein?

Binds to the operator to physically blocks

the RNA polymerase from the promoter

site.

BINDS HERE

BLOCKS THE

PROMOTER

7/28/2019 PP Gene Regulation

19/27

7/28/2019 PP Gene Regulation

20/27

EUKARYOTIC GENE REGULATION Eukaryotic DNA has exons and introns.

What are exons?

The coding regions of DNA that are expressed into

proteins.

What are introns?

Non-coding regions of the DNA.

7/28/2019 PP Gene Regulation

21/27

EUKARYOTIC GENE REGULATION

7/28/2019 PP Gene Regulation

22/27

EUKARYOTIC GENE REGULATION

7/28/2019 PP Gene Regulation

23/27

CELL DIFFERENTIATION

7/28/2019 PP Gene Regulation

24/27

CELL DIFFERENTIATION

One chromosome may have several genes.

Not all the genes will be transcribed and

translated.

The genes that are transcribed and translated

determine the type of cell.

7/28/2019 PP Gene Regulation

25/27

CELL DIFFERENTIATION

So these cells all have the exactsame DNA, but each cell uses

different segments of the DNA

during transcription.

7/28/2019 PP Gene Regulation

26/27

TRANSCRIPTIONFACTORS

http://www.youtube.com/watch?v=MkUgkDLp2iE

http://www.youtube.com/watch?v=MkUgkDLp2iEhttp://www.youtube.com/watch?v=MkUgkDLp2iE

7/28/2019 PP Gene Regulation

27/27

4.46

TRP OPERON

http://www.youtube.com/watch?v=10YWgqmAEsQ

http://www.youtube.com/watch?v=10YWgqmAEsQhttp://www.youtube.com/watch?v=10YWgqmAEsQ