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13 Cards in this Set
- Front
- Back
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What is epigenetics? |
Provides explanations as to how environmental influences can alter genetic inheritance. eg: diet, stress, toxins. |
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What are chemical tags? |
Chemical tags cover the DNA histone complex and determine the shape of the DNA-histone complex. |
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What is the epigenome? |
The epigenome is the culmination of all chemical tags and is comprised of these chemical tags. |
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What can cause chemical tags to be altered? |
Environmental factors (eg: diet, stress, toxins). |
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What is epigenetic silencing? |
This is when chemical tags cause DNA to wrap tightly around histones, preventing the DNA from being read and preventing the binding of transcriptional factors. |
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What is the opposte of epigenetic silencing? |
Active genes are wrapped loosely around histones allowing access for transcriptional factors and allowing the gene to be 'read'. |
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Name 2 ways in which changes to the environment can inhibit transcription via the epigenome. |
Decreased acetylation of associated histones
Increased methylation of DNA |
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How can decreased acetylation of associated histones inhibit a gene? |
increased positive charge on histones
Histones become more attracted to -ve phosphate groups on DNA. Stronger DNA histone association, no longer accessible to transcriptional factors. |
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How can increased methylation of DNA inhibit a gene? |
1) can prevent transcriptional factors from binding to DNA. 2) Proteins are attracted which condense the DNA histone complex by decreased acetylation, making DNA inaccessible. |
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How can epigenetics be used to treat disease? |
By using drugs to target transferase enzymes which cause methylation of DNA or changes to acetylation. This could switch on/off genes which were previously wrongly switched on/off. |
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What mechanism does siRNA affect? |
Translation of mRNA intro proteins. |
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What is siRNA |
Small interfering RNA A short piece of double stranded RNA with a complementary sequence to the target mRNA. |
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How does siRNA inhibit translation |
siRNA unravels and joins with an ezyme. siRNA pairs with the target mRNA, interfering with translation and stopping gene expression. The enzyme digests mRNA |
