Environmental Effects and Epigenetics

Question 1

What are housekeeping genes

Answer 1

Genes that code for common structural proteins/enzymes

Question 2

What are specialised genes

Answer 2

Genes that code for proteins that differentiate cells

Question 3

How is transcription initiated

Answer 3

Basal machinery factors unwind DNA
TATA box indicated start site
General transcription factors bind + start transcription + recruit RNA polymerase

Question 4

How is the gene regulated

Answer 4

Transcription factors receive messages from inside/outside of cells eg. phosphate levels

Question 5

What determines the rate of transcription

Answer 5

Multiple enhances upstream/downstream

Transcription activators

Question 6

Describe the structure of chromatin

Answer 6

Chromosome = One centromere. 2 telomeres
Histone Protein = Pack DNA into repeating DNA-Pn Particles
Nucleosome = 8 Histones and associated DNA

Question 7

What is the function of histone modification

Answer 7

Carry information
Regulatory information
Layer of information that overlays DNA sequence

Question 8

What do nucleosome modifications do

Answer 8

Turn genes on/off

Respond to changes in internal/external environment

Question 9

What happens in X inactivation

Answer 9

1 of 2 X inactivated during early development
Inactivated X packaged into chromatin, condensed and turned into stone
Affects dosage compensation

Question 10

Women have same X gene products as men but men only have 1 X chromosome. Why?

Answer 10

Gene dosage compensation = equalises gene expression levels