Epigenetics

Question 1

Epigenetic

Answer 1

Altering of Gene expression/phenotypes/appearance without change in the gene structure

Question 2

Epigenetic factors

Answer 2

Factors that make genes more or less likely to be expressed, may be inherited.

Question 3

Geneome

Answer 3

A person’s Hereditary information that is encoded in their DNA

Question 4

Epigenome definition

Answer 4

Is the sum of all the factors that determine when, where, and which genes are ‘switched on’ or expressed.

Question 5

what does an epigenome do

Answer 5

It controls which genes are active in a cell, therefore which proteins will be produced.

Question 6

What happens if an epigenome is abnormal

Answer 6

If an epigenome is abnormal a cell can be abnormal and a disease may occur

Question 7

Ways where genes are regulated epigenetically

Answer 7

1. chromatin
2. DNA acetylation
3. DNA methylation

Question 8

Chromatin method

Answer 8

Is one way that genes can be regulated epigenetically

DNA molecules are in the form of long strands that are 2-3m long, tightly coiled around the histone proteins in the nucleus.

When a cell is not dividing, the coiled DNA forms a tangled network.

It physically opens or closes DNA to control whether genes can be read.

Question 9

Modified histones

Answer 9

A modified histone is a histone protein that has had chemical groups added to it (Methyl, acetyl), They change how tightly DNA is wrapped around the histones influencing gene expression.

Question 10

Acetylation (histone modification)

Answer 10

Acetyl tails protrude from the histones
This affects how tightly the DNA can wrap around the histones and the distance between the histones.

Acetylation, therefore, produces more loosely bound DNA.

These sections of DNA can more easily interact with RNA polymerase complex to be transcribed.

More mRNA can be produced resulting in more protein produced.

It is more open to be expressed, or these genes are switched ‘on’

Question 11

DNA methylation (chromatin remodelling)

Answer 11

Methyl groups are added to the DNA strand at CpG sites (cytosine – phosphate – guanine)

These groups interfere with RNA polymerase being able to bind to the DNA in order for the gene to be transcribed

Less transcription means that less protein is made.

Therefore, methylation inhibits gene expression, or switches the genes off

Question 12

Gene regulation factors affecting gene

Answer 12

Acetylation - on

Deacetylation - off

methylation - off

demethyltion - on

Question 13

Factors that cause epigenetic changes in DNA

Answer 13

Diet and Nutrition

Environmental toxins

Drugs and alcohol

stress and trauma

radiation and UV light

Physical activity

Temperature

Question 14

how does epigenetics have a link with transcription

Answer 14

Transcription = making an mRNA copy of a gene → so the gene is ON and can make a protein.

Epigenetics controls whether transcription can happen by changing how tightly DNA is packed