Gene Regulation

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  • Created by: gemmmmma
  • Created on: 16-06-18 19:59
How does chromatin remodelling affect transcription?
Transcription is not possible with heterochromatin (tightly wound) because RNA polymerase cannot access the genes.
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Why doesn't proteinsynthesis occur during cell division?
Ensures the proteins necessary for cell division are synthesised in time. Prevents protein synthesis occuring when the cell actually divides.
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How does acetylation or phosphorylation affect transcription?
Reduces positive charge of histones and causes DNA to coil less tightly - allowing transcription
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How does methylation affect transcription?
Makes histones more hydrophobic so they bind more tightly - reducing transcription.
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What does lacZ code for?
B- galactosidase, which breaks down lactose into glucose + galactose
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What does lacY code for?
lactose permease, which allows lactose entry
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Outline the action of the lac operon.
1) Usually repressor gene codes for lacI, which blocks promoter and operator. (2) if lactose present it binds to lacI and changes its shape so it cannot block promoter. (3) RNA polymerase is able to trigger the transcription of lacZ and lacY.
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Outline post-transcriptional control via RNA processing
A cap is added to the 5', and a tail is added to the 3' end of pre-mRNA. Help stabilise and prevent degradation. Cap also aids binding to ribosomes. Introns are removed and exons joined together.
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How does RNA editting affect gene control
Nucleotide sequence of RNA can be changed through addition/deletion/substitution. Will change amino acid produced.
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Outline mechanisms of translational control
1) Degradation of mRNA (how long it lasts). (2) Binding of inhibitory proteins prevents proteinsynthesis. (3) Activation of inititiation factors aid mRNA binding to ribosome.
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How can protein kinases influence translational control
Enzymes that catalyse the addition of phosphate groups to proteins. Addition of a phosphate group changes the tertiary structure and function of the protein. Often activated by cAMP.
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Outline mechanisms of post translational control
1) Addition of non-protein groups (2) modifying amino acids and bonds (3) folding/shortening of proteins (4) modification of cAMP.
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Other cards in this set

Card 2

Front

Why doesn't proteinsynthesis occur during cell division?

Back

Ensures the proteins necessary for cell division are synthesised in time. Prevents protein synthesis occuring when the cell actually divides.

Card 3

Front

How does acetylation or phosphorylation affect transcription?

Back

Preview of the front of card 3

Card 4

Front

How does methylation affect transcription?

Back

Preview of the front of card 4

Card 5

Front

What does lacZ code for?

Back

Preview of the front of card 5
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