week 12: control of gene expression in eukaryotes

Question 1

importance of chromatin remodelling

Answer 1

nucleosomes are very tightly packed so it has to be loosened up to make DNA more accesible. done through chemical modifications like acetylation, which loosens histone grip on DNA

Question 2

what is epigenetic modification

Answer 2

changes in gene expression and phenotype (sequence itself is not altered). can happen due to enviromental factors. eg methylation causes histones to become more compact and make DNA less accessible

Question 3

the two types of transcription factors

Answer 3

general - binds to promoters, leadings to low transcription
specialist - bind to enhancers and silencers. activator TF binds to enhancers (trans. up), repressor TF bind to silencers (trans.low)

Question 4

examples of post transcriptional control

Answer 4

alternative splicing and polyadenylation -
mRNA transport
RNA interference -

Question 5

translational control

Answer 5

translation initiation - controlled by 5’ cap and poly A tail. circularised mRNA stimulates recruitment of small ribosomal subunit then the large subunit, thus beginning translation.

Question 6

examples of post translational control

Answer 6

protein folding, modification, targeting, turnover