The result of the selective expression of certain genes out of the full set found in every cell.
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What are transcriptional factors?
Specific molecules that move from the cytoplasm into the nucleus.
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What happens when a transcriptional factor binds to a region of DNA?
It stimulates the region of DNA to begin transcription.
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What is the effect of an inhibiting molecule on transcription?
It occupies the site on the DNA which the transcriptional factor would normally attach to. This molecule prevents the transcriptional factor binding and so prevents transcription and polypeptide synthesis.
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How do hormones switch on genes?
By combining with a receptor on the transcriptional factor and releasing the inhibiting molecule.
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How can oestrogen cross the phospholipid bilyaer?
It is lipid soluble.
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What does oestrogen do to receptor molecules on the DNA?
It binds to the receptor molecule, changing its shape and as a result causing the inhibiting molecule to be released, allowing the transcriptional factor to bind with the molecule.
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Where does the work of oestrogen on the DNA receptor molecule take place?
In the cytoplasm of a cell.
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How can gene expression be prevented (in terms of RNA)?
By breaking down mRNa before its genetic code can be translated into a polypeptide.
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What is the section of RNA called that is responsible for the breakdown of mRNA?
Inteferring RNA.
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How does inteferring RNA break down mRNA?
It binds with an enzyme and directs this enzyme to the mRNA. Then, the enzyme cuts the mRNA into smaller sections which means it is no longer capable of being translated into a polypeptide and is essentially blocked.
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How can SIRNA be used in medicine?
1- to identify the roles of genes in a biological pathway, 2- As some diseases are caused by genes, it may be possible to use SIRNA to block these genes and so prevent the disease.
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Other cards in this set
Card 2
Front
What are transcriptional factors?
Back
Specific molecules that move from the cytoplasm into the nucleus.
Card 3
Front
What happens when a transcriptional factor binds to a region of DNA?
Back
Card 4
Front
What is the effect of an inhibiting molecule on transcription?
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