Epigenetics

Question 1

epigenetics

Answer 1

• heritable change in gene function without altering DNA base sequence
• caused by environment e.g. diet, toxins

Question 2

epigenome

Answer 2

• single layer of chemical tags on the DNA, which are all chemical modifications to histone proteins and DNA
• affects shape

Question 3

heterochromatin

Answer 3

• tightly coiled DNA

Question 4

chromatin

Answer 4

• loosely coiled DNA

Question 5

Methylation

Answer 5

• increased methylation inhibits transcription
• attach to cytosine base
• prevents transcription factors from binding
• attracts proteins that condense DNA-histone complex

Question 6

Acetylation

Answer 6

• decreased acetylation inhibits transcription
• if r removed histones become more positive and are attracted more to the phosphate group on DNA
• makes DNA and histones strongly associated
• harder for transcription factors to bind

Question 7

Tumour suppressor genes

Answer 7

• produce proteins that slow down cell division and cause cell death if errors are detected
• if mutation occurs they cannot carry out function which could lead to breast cancer
• BRAC1 BRAC2

Question 8

TSG hypermethylation

Answer 8

• increased number of methyl groups attached results in gene being inactivated and turns off

Question 9

Oncogene

Answer 9

• mutated genes that can cause cancer through deregulation of cell growth

Question 10

ONC hypomethylation

Answer 10

• reduces number of methyl groups attached
• gene permanently switched on
• triggers mitosis to constantly occur