Topic 14- Gene Regulation

Question 1

Why is gene regulation important

Answer 1

So that cells know what kind of cell they need to be. by regulating if a gene should be on or off and how much or how little it should be expressed.

Question 2

What are Operons?

Answer 2

Only in bacteria.

Stretch of DNA that has an Promoter, Operator, and Genes

Question 3

Describe the two types of Operons with examples.

Answer 3

Repressible Operons- Genes usually on but can be turned off.
ex. TRP Operon found in E coli is usually on but when there is already tryptophan in the environment it turns off because it binds with a repressor protein activating it which allows it to bind to the operator zone which blocks Polymerase from reaching it.

Inducible Operons- Usually off but can be turned on.
ex. IAC Operon is usually off but when in the presence of lactose it binds with the repressor proteins on the operator, inactivating it causing it to fall of and allow the gene to be expressed.

Question 4

Describe Gene regulation in eukaryotes.

Answer 4

Done through DNA packing which is when the DNA is wrapped around protein complexes called nucleosomes.

Condensed Chromatins are when the DNA is tightly wound and cannot be expressed because the RNA polymerase cannot reach it. Heterochromatin

Decondensed Chromatin are when it is less condensed and it can be expressed. Euchromatin .

When a cell does not need a section of DNA it adds an acetyl group to it to loosen it. No acetyl tightens it.