5. Epigenetic Control of Gene Expression + Evaluating Data on Phenotypes.

What does epigenetic control do?

Determines whether a gene is switched on or off/ expressed or not.

Read first 2 paragraphs on page 466 Biology CGP book for summary.

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List two chemical markers

methyl groups

acetyl groups

Where do methyl groups attatch to

CpG site where cytosine and guanine base are next to each other in the DNA.

The effects of increased methylation of DNA on gene expression.

Increased methylation changes the DNA structure so that the transcriptional machinery can’t interact with the gene - so the gene is not expressed.

what are histones

proteins that DNA wraps around to form chromatic, which makes up chromosomes.

what is acetylation

addition or removal of acetyl groups

the effects of acetylation on acetyl groups

when histones are acetylated, chromatin is less condensed, so transcriptional machinery can access the DNA, allowing genes to be transcribed.

what enzymes are responsible for removing acetyl groups

deacetylase (HDAC)

Read development of disease = page 467 to page 470.