Topic 4

Question 1

snRNA

Answer 1

small nuclear RNA
- splicing process in Eukaryotes

Question 2

miRNA

Answer 2

microRNA
- regulating genes (short pieces)

Question 3

siRNA

Answer 3

small interfering RNA
- antisense, opposite to normal RNA sequence

Question 4

RNA polymerase

Answer 4

unwinds DNA & produces RNA transcript from DNA template
- 5’ to 3’

Question 5

TSS

Answer 5

Transcription Start Site
- +1
- first transcribed base

Question 6

Promoter

Answer 6

bases preceding the initiation site
- upstream, 5’ direction

Question 7

Coding bases

Answer 7

downstream of initiation site
- 3’ direction

Question 8

UTR

Answer 8

Untrnaslated region
- usually on both the 3’ and 5’ ends of most genes
- transcribed but not translated

Question 9

Consensus promoter sequence

Answer 9

-35 and -10 regions

Question 10

holoenzyme

Answer 10

RNA polymerase
- 2 alpha + 1 beta + 1 beta’ + 1 sigma subunits
- scans DNA and sigma subunit binds promoter elements to position enzyme
- after binding, sigma unit falls off and remaining subunits form RNA polymerase core enzyme

Question 11

intrinsic termination

Answer 11

formation of GC-rich hairpin loop followed by 6-8 A’s in template
- only needs the sequence, not any other factor or protein

Question 12

rho dependent termination

Answer 12

binding of rho hexamer to rut (rho utilization) site, pausing RNA polymerase, rho-mediated dissociation

Question 13

GTF

Answer 13

general transcription factors

Question 14

PIC

Answer 14

Pre-initiation complex
- formed by the binding of GTF to promoter and the attraction of RNA poly II complex

Question 15

TATA box

Answer 15

common promoter sequence at -30bp
- binding site of TATA binding protein (TBP)

Question 16

CTD

Answer 16

carboxy terminal domain
- protein tail of the beta subunit of RNA poly II
- ends initiation, when phosphorylated by a DTF
- weakens connection of RNA Poly II to other PIC proteins

Question 17

contranscriptional

Answer 17

translation occurs simultaneously with transcription

Question 18

conserved sequence

Answer 18

evolutionary relationship between organisms

Question 19

AAUAAA or AUUAAA

Answer 19

conserved sequence that terminates transcription
- RNA is cleaved 20 bp downstream

Question 20

5’ capping

Answer 20

7-methylguanosine linked to 5’ end by 3 phosphates (P-P-P-G)
- for protection/stability3

Question 21

3’ poly-A-tail

Answer 21

polyadenylation
- 150-200 A residues added to 3’ end by poly (A) polymerase (template independent polymerase)
- for stability, protect from RNases

Question 22

Splicing

Answer 22

introns removed, leaving exons only
-conserved sequences mark splice sites (GU-AG rule)
-occurs by Lariat formation

Question 23

spliceosomes

Answer 23

includes snRNAs

Question 24

Degenerate code

Answer 24

64 codons possible, but only 20+ needed, many amino acids have multiple codons

Question 25

AUG

Answer 25

methionine, start codon

Question 26

tryptone codon

Answer 26

UGG

Question 27

reversion

Answer 27

revert mutation back to wild type (@ same mutation site)

Question 28

suppression

Answer 28

2 mutations cancel each other out (@ different mutation sites)

Question 29

Stop codons

Answer 29

UAG, UGA, and UAA

Question 30

amicoacyl-tRNA synthetase

Answer 30

catalyzes charging rxn of tRNA (attachment of aa onto tRNA)

Question 31

wobble pairing

Answer 31

some tRNA anticodons can pair with multiple codons
- G + U/C
- C + G
- A + C
- U + A/G
- I + U/C/A

Question 32

Ribosome subunits

Answer 32

Large:
- euk. = 60S
- pro. - 50S
Small:
- euk = 40S
- pro. = 30S

Question 33

A binding site

Answer 33

amicoacyl
- first site
- binds incoming aa-tRNA

Question 34

P binding site

Answer 34

peptidyl
- contains growing peptide chain

Question 35

E binding site

Answer 35

exit
- contains deacylated tRNA

Question 36

Shine Delgaro sequence

Answer 36

precedes initiation codon
- signals ribosome binding
- pairs with small ribosomal subunit