Epigenetics Flashcards

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1
Q

What is epigenetics?

A

changes in gene expression, usually caused by a change in the environment

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2
Q

What is meant by the term ‘epigenome’?

A

all of the chemical tags on the DNA of an organism

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3
Q

Why is DNA not transcribed when methyl groups are bound?

A

As transcription factors cannot bind

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4
Q

What is methylation?

A

adding on a methyl group

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5
Q

Where do methyl groups attach to DNA?

A

on the Cytosine base

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6
Q

What does increased methylation result in?

A

less transcription so less gene expression

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7
Q

why does increased methylation reduce transcription?

A
  • methyl groups prevent transcription factors from binding
  • methyl causes proteins which increase acetylation, reducing gene expression
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8
Q

What is acetylation?

A

the addition of acetyl groups to the histones

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9
Q

What does DECREASED acetylation result in?

A

inhibited transcription

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10
Q

Why does increased acetylation result in increased transcription?

A

histones become neutral, so sections of DNA exposed therefore transcription factors can bind

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11
Q

What makes the DNA negatively charged?

A

phosphate groups

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12
Q

Describe deacetylation and its impact on gene expression…

A
  • acetyl groups are removed from histones
  • causes the histones to become positively charged
  • negatively charged phosphate groups are attracted to the positively charged histones
  • DNA becomes more tightly coiled
  • so transcription factors cannot bind so the gene is not expressed
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13
Q

What adds and removes epigenetic tags?

A

enzymes

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