Cmb2001 - Study guides, Class notes & Summaries

CMB2001 EXAM WITH VERIFIED ANSWERS AND QUESTIONS ...

CMB2001 EXAM QUESTIONS AND VERIFIED ANSWERS..

CMB2001 FINAL EXAM (326) QUESTIONS WITH VERIFIED ANSWERS ...

CMB2001 TEST QUESTIONS WITH CORRECT ANSWERS...

CMB2001 TEST QUESTIONS AND ANSWERS...

What is gene expression? ~~> dsDNA is decoded to ssRNA/proteins by an mRNA intermediate using A/U/C/GTPs and RNA polymerase Where is the consensus sequence in prokaryotic promoters? ~~> at -10 and -35 upstream of the the transcription start site What recognises the consensus sequences in prokaryotes? ~~> the holoenzyme What is a holoenzyme? ~~> a closed complex with a core enzyme and sigma factor 70 What does the holoenzyme do? ~~> causes the dsDNA to open and allo...

Describe how H3Lys9me heterochromatin is formed ~~> H3Lys9me heterochromatin formation: Lys9 deacetylated by HDAC. Suvar39 then methylates lys9. Methylated lys9 is recognised by HP1 and then HP1 binds. HP1 has chromodomain - chromodomains often recognise and bind to methylated lys residues. Chromodomain on HP1 is specific for H3Lys9me (with di or tri methylated lys 9). Binding of HP1 is thought to compact nucleosome arrays as HP1s join together. What is gene expression? ~~> ...

Why does RNA degradation take place? ~~> Damaged mRNA Incorrectly transcribed/processed mRNA Control gene expression What 2 things control mRNA levels? ~~> Transcription and turnover Why is turnover important? ~~> If mRNA has a ridiculously long half life and doesn't go away, then if you stop transcription you don't stop protein expression because the mRNA is still there Describe what casein mRNA is and explain the importance of turnover ~~> Expressed in mammar...

Eukaryotic promoters have a basal region which can contain a TATA box, initiator (Lnr), BRE (TFIIV recognition element) and what other element? ~~> Downstream core promoter (DPE) In prokaryotes RNA polymerase requires what co-factor? ~~> 70 sigma factor Forms the holoenzyme The promoter is formed of two hexameric sequences at what positions? ~~> -35 and -10 The amount of product transcribed is dependant on how close the promoter sequences are to what? ~~> Consensus s...

Core Promoter Elements ~~> TATA box = repetitive sequence of thymine and adenine Initiator (INR) = sequence of pyramidines like thymine and cytosine DPE = downstream promoter elements found along the DNA Common to have >1 promoter but not all of them CpG islands ~~> Sequences high in CG frequency. They are able to escape methylation which would lead to gene silencing. Demethylation would lead to over expression of genes. Regulatory Promoter Elements ~~> UAS and URS f...