L9 what is gene and transc

Question 1

LO2: desc proc transc.
LO3: list and summ maj reacs in RNA maturat in euk and expl imp gene exp.

Answer 1

-gene exp- making polynt/pep.
dna replic- DNAP, dNTPs, DNA templ.
transc- RNAP, NTP, DNA templ.
transl- ribosome, aa, RNA templ.
all init, elong, termin.
TRANSC: make mRNA polynt. Pdiest bond rels PPi.
-INIT- prom recog. prom tells direc. recog seq in 5’ to 3’. TF bind. RNAP bind. +1 base=TSS. upstr is 5’ from here. prom often far upstr TSS.
-ELONG- DNA cod str and mRNA both complem to templ/non cod. templ read 3’ to 5’. 5’ to 3’ chain growth. TF bind cod str. forms pre mRNA.
-POST TRANSC-
capp- met guan connec to 5’ to 5’ by 3P. protec ag deg and role transc.
polyA- specif endonuclease recogs and cuts=free end 3’. polyA polymerase adds 200 A from ATP. protec deg. seq btw polyA and next TSS deg.
splicing- rem introns seq dep. prot complex form, loop mRNA, bound, spliced, ligat. splicosome, lot prot, v regul, defec. eg intron skipp pku.
mat mRNA has utr’s and orf.

Question 2

LO3: comp and contr gene exp in euk and bact and expl how diff exploit clinic.

Answer 2

transc init-

• euk- TATA box -30. var upstr seqs- prots binds and regul, can be far from gene. complex regul.
• prok- pribnow -10. upstr seqs -35. simp regul.

Question 3

LO1: define gene.

Answer 3

-stretch DNA, chrom locus. encodes prots and regulat. 2x25000/cell. unit of inher/transc. heteroch not exp. allele= vers gene.