21945100
Description
Flashcards by Evian Chai, updated more than 1 year ago
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Created by Evian Chai
over 4 years ago
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| Question | Answer |
| When is gene expression regulated? | 1. Cell differentiation/development 2. In response to environment (food/hormones) |
| What is the major point of gene expression regulation? | Transcription |
| What are transacting molecules? What do transacting molecules bind to? | Molecules (usually proteins) that are synthesised by a gene other than the targetted one Bind to Cis acting elements by diffusing through cell |
| What type of molecule is General Transcription Factors that initiate transcription? | Transacting molecule |
| What are regulatory sequences? Where are they located? Why are they considered "cis"? What is an example? | 1. Short DNA sequences in noncoding regions that control transcription initiation 2. Cis because they act on genes on the same DNA molecule 3. TATA Box |
| What is the TATA Box, where is it, and what does it do? | Short consensus sequence from 34-26 UPSTREAM the start codon (can be in promoter region) Positions RNA Polymerase II for transcription initiation |
| Where is the promoter found in relation to the coding region? What occurs at this region? | The promoter is found in the 5' upstream section of the coding region The transcription initiation complex is assembled |
| What do general transcription factors do? | Bind DNA to form the preinitiation complex+recruit RNA Polymerase II at the promoter region |
| What do sequence specific DNA binding TFs do? Where do they bind? | enable/prevent specific promoters Upstream promoter sequence |
| What are two ways hormones can influence gene expression? | 1. Bind to receptors on cell membrane, starting a signalling cascade 2. Bind to receptor, which translocates to nucleus to stimulate transcription initiation |
| How can gene expression be regulated during the polyadenylation of RNA? | UIA protein binds to own mRNA to inhibit polyadenylation (negative feedback loop) |
| How does differential/alternative splicing of RNA allow for gene regulation? | Different EXONS on same gene selectively removed to create different DNA sequences |
| How does fibronectin differ in the liver and fibroblasts? | Fibroblasts make ADHESIVE fibronectin that sticks to ECM Liver makes fibronectin w adhesive properties spliced out, so can circulate in body |
| Why does gene expression need to be controlled? | Wasteful to make unneeded proteins |
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