Regulation of Gene Expression

Question 1

What does the Lac operon bind to?

Answer 1

Repressor protein at operator - vacant for gene to be active
Binds to CAP for full transcription activity

Question 2

What are two histone modifications and their enzymes?

Answer 2

Acetylation by HAT
Deacetylation by HDAC

Question 3

What does cytosine methylation do?

Answer 3

Hypermethylation turns gene off
Hypomethylation turns gene on

Question 4

What are variations in DNA?

Answer 4

Histone and DNA modifications
Amount of DNA
Arrangement of DNA
Mobile elements

Question 5

What is used for regulation in transcription?

Answer 5

Trans-acting molecules
Cis-regulatory elements
Alternative splicing
mRNA editing
miRNA

Question 6

What are cis-acting elements?

Answer 6

Sequence in DNA on same chromosome
Response elements

Question 7

What are enhancer DNA sequences?

Answer 7

Increase transcription
Bound by activator proteins

Question 8

What are silencer DNA sequences?

Answer 8

Reduce transcription of gene
Bound by repressor proteins

Question 9

What are transacting elements?

Answer 9

Control genes on same or different chromosomes
Encode for trans activators - specific TFs

Question 10

What are hormone response elements?

Answer 10

DNA sequences that bind transacting proteins in response to hormonal signals

Question 11

What is miRNA (microRNA)?

Answer 11

Small, noncoding
Target RNA for degradation - reduce amount of mRNA
Works in complex with proteins