Gene expression Flashcards
1
Q
rRNA
A
> 80% of total RNA
- few kinds, many copies
- small and large rRNAs
- highly conserved
2
Q
tRNA
A
less than 15%
small
each one dedicated to one of 20 amino acids
3
Q
mRNA
A
2-5% of total RNA
4
Q
what do you need for transcription
A
making RNA
template- DNA
enzyme- RNA polymerase
substrate- NTPs- ribonucleotides
5
Q
how is RNA synthesised
A
5’ to 3’
DNA read 3’ to 5’
6
Q
what is needed for promoter binding
A
transcription factors
7
Q
Trancription initiation
A
- transcription factor binds promoter
- binding is directional on TATA box
- RNA polymerase recruited
- unwinding DNA helix
- formation of a transcription bubble
- transcription initiates, directionally 5’-3’
8
Q
what is the TATA box
A
specific sequence on all promotor sequences
9
Q
transcription elongation
A
- RNA synthesis from 5’ - 3’
- template strand is read 3’ - 5’
- single stranded RNA molecule is made
- only one DNA strand is used as a template
-as transcription bubble advances, DNA helix reforms behind it
10
Q
coding strand
A
non-transcribed DNA strand
11
Q
non-coding starnd
A
transcribed DNA strand
12
Q
transcription termination
A
- sequence-dependant, other factors involved
- results in a primary RNA molecule
- RNA processing needed to produce mature RNA
13
Q
RNA processing
A
- post-translational modifications
- rRNA and tRNA
- chemical modicfications and cleavage
- mRNA
- eukaryotes|: capping, splicing and tailing
14
Q
Capping
A
5’ cap
methylated-g linked 5’-‘5’
provides protection
plays role in translation
15
Q
tailing
A
3’ poly A tail
for protection and reglation
