L9 RNA and Transcription

Question 1

Is RNA stable?

Answer 1

no, unstable intermediates

Question 2

when looking at a ribose, how can you tell if it is DNA or RNA?

Answer 2

RNA has a 2’ OH where DNA has a 2’ H

Question 3

mRNAs

Answer 3

intermediates that carry genetic information from DNA to ribosomes (coding)

Question 4

tRNAs

Answer 4

adaptors between amino acids and the codons in mRNA

Question 5

rRNAs

Answer 5

structural and catalytic components of ribosomes

Question 6

snRNAs

Answer 6

structural components of spliceosomes

Question 7

miRNAs

Answer 7

short single-stranded RNAs that block translation of complementary mRNAs

Question 8

template strand

Answer 8

DNA strand that is copied via complementary base pairing during transcription

Question 9

the non-template strand is complementary to what? and shares sequence with what

Answer 9

template strand, mRNA have same sequence

Question 10

does RNA pol require a primer?

Answer 10

no

Question 11

initiation of RNA chains, 3 things

Answer 11

-binding of RNA pol to promoter in RNA
-localized unwinding of the two strands of DNA by RNA polymerase to provide a single stranded template
-formation of phosphodiester bonds between the first few ribonucleotides in the nascent RNA chain

Question 12

what does the promoter do?

Answer 12

attracts RNA polymerase to the start of a gene

Question 13

what is RNA pol made of?

Answer 13

several subunits, core enzyme and sigma factor

Question 14

what does the sigma factor do?

Answer 14

recognizes the -35 sequence

Question 15

where is DNA unwound at to form an open complex?

Answer 15

-10bp

Question 16

rho-independent termination

Answer 16

-transcription of inverted repeats
-transcription of 6 A’s, rapid folding of RNA into “hairpin”
-RNA pol pauses and the H-bonds break and transcript is released from DNA

Question 17

in Euks, RNA pol2 binds to what?

Answer 17

promoter sequences with aid of transcription factors

Question 18

steps of RNA processing in Euks?

Answer 18

pre-mRNA
addition of 5’ cap
addition of poly-A tail
splicing introns
mature mRNA

Question 19

C-terminal domain of RNA pol2

Answer 19

-consists of repeats of a 7 amino acid sequence
-is phosphorylated during transcription initiation

Question 20

what does the 5’ cap do?

Answer 20

-protect mRNA from degradation
-enhances translation by orienting the ribosome on the mRNA
-facilitating subsequent intro spliicng
-facilitates transport of mRNA out of nucleus

Question 21

polyadenylation

Answer 21

adding a tail to 3’ end of transcript to facilitate transport of mature mRNA across the nuclear membrane to cytoplasm. protect from degradation

Question 22

exons

Answer 22

pieces of pre-mRNA sequence that end up in mature mRNA

Question 23

introns

Answer 23

pieces of mRNA sequence that are removed during processing