Epigenetics

Question 1

What is epigenetics

Answer 1

Study of changes in organisms caused by modification of gene expression rather than alteration of genetic code itself, Epi- on top, Genetics- the genes

Question 2

Epigenetic tags

Answer 2

Can be permanent or temporary, can be inherited by modified epigenetic factors in the gametes- can be passed down through 3 generations (Grandma, mother, daughter), May be the cause of many cancers and diseases

Question 3

What else can effect genes

Answer 3

Environmental factors such as cigarette smoke can methylate cytosine or deacetylate the histones in turn meaning that the gene that prevents lung cancer is turned off meaning lung cancer develops

Question 4

What is DNA methylation

Answer 4

Addition of a methyl group (CH2), usually to cytosine

Question 5

What does DNA methylation cause and when does it occur

Answer 5

Prevents transcription of the methylated portion of DNA- represses gene expression, Occurs during cell differentiation

Question 6

What is histone acetylation

Answer 6

Addition of a acetyl group to the histone protein

Question 7

What does adding an acetyl group cause

Answer 7

causes the histone to be negatively charged which then repels the negatively charged DNA, DNA loosens around the histone which leaves uncondensed DNA that is accessible to transcription factors such as RNA polymerase

Question 8

What is histone deacetylation

Answer 8

represses the expression of DNA, silences the gene

Question 9

How else can genes be changed

Answer 9

other histone modifications- epigenetic tags added such as phosphate, ubiquitin, methyl and acetyl