Epigenetic control of gene expression

Question 1

Define epigenetics

Answer 1

The study of the effect of environmental influences on the genetic inheritance of an organisms offspring

Question 2

What does the epigenome determine?

Answer 2

The shape of the DNA histone complex

Question 3

What is the epigenome?

Answer 3

All of the chemical tags in a DNA molecule

Question 4

What environmental factors can affect the epigenome?

Answer 4

Diet
Stress
Toxins

Question 5

Describe how decreased acetylation affect DNA and gene expression?

Answer 5

Decreased acetylation increases the positive charges on the histones
This increases their attraction to phosphate groups on the DNA
DNA histone complex coils more tightly, preventing transcription factors from binding
Gene cannot be expressed

Question 6

What ways does increased methylation affect gene expression?

Answer 6

Prevents binding of transcription factors

Attracts proteins that induce deacetylation

Question 7

How can disease be treated using epigenetic therapy?

Answer 7

Use drugs that inhibit enzymes that cause DNA methylation

Inhibit enzymes that cause deacetylation

Detect levels of methylation and deacetylation in order to combat disease early

Question 8

What is small interferring RNA?

Answer 8

RNA used for switching off genes for short term

Question 9

Describe the mechanism of siRNA action to prevent translation of a gene

Answer 9

Double strand RNA is broken up into siRNA using an enzyme
One siRNA strand combines with an enzyme
siRNA guides enzyme to mRNA by pairing with complementary bases on mRNA strand
Enzyme cuts mRNA into smaller strands, preventing translation