Molecular Bio 5

Front 1

Transcription

Back 1

nucleotide sequence of DNA is transcribed into RNA

Front 2

What are the chemical differences between RNA and DNA?

Back 2

ribose/deoxyribose

uracil/thymine

Front 3

RNA

Back 3

mostly single stranded
leads to complementarity leads to secondary structures

Front 4

What are the functions of RNA?

Back 4

1. RNA as a genome
2. carrier of information - mRNA
3. protein synthesis - rRNA and tRNA
4. catalytic - ribozymes, autocatalytic RNAs, peptidyl transferase

Front 5

What is the order of abundance and location of RNA?

Back 5

rRNA (ribosomes and nucleolus) > tRNA (cytoplasm) > mRNA (nucleus and cytoplasm)

Front 6

Where does the termination occur?

Back 6

at a hairpin loop

Front 7

What's the first step of transcription?

Back 7

RNA polymerase binds to promoter region

Front 8

After RNA polymearase binds to the promoter region...

Back 8

the double stranded DNA opens

Front 9

When RNA transcription in initiated with...

Back 9

no primer required, no proofreading occurs (error rate - 1/10,000)

Front 10

RNA sequence is ____to template strand and _____ to coding strand.

Back 10

complementary to template
equivalent to coding

Front 11

simplest RNA polymerase

Back 11

single polypeptide
ie T3 and T7 bacteriophages

Front 12

e. coli RNA polymerase

Back 12

5 subunits + w subunit

Front 13

yeast RNA polymerase

Back 13

12 subunits

Front 14

What part of the RNA polymerase recognizes the promoter sequence?

Back 14

alpha subunit

Front 15

promoter strength=

Back 15

rate of transcription

Front 16

core enzyme RNA

Back 16

(alpha alpha beta beta') and w

Front 17

holoenzyme

Back 17

core enzyme + sigma subunit

Front 18

promoter recognition and sigma

Back 18

1. core enzyme can bind any DNA
2. holoenzyme forms and binds a promoter -"closed complex"
3. polymerase unwinds the DNA "open complex"
4. transciption begins and after 10 nucleotides sigma dissociates
5. polymerase pries RNA off the template
6. RNA synthesis becomes efficient "elongation phase"
7. termination signal encountered: polymerase dissociates from DNA

Front 19

e. coli terminators

Back 19

stop transcription at specific sites without any factors

Front 20

the intrinsic terminator has two features, which are:

Back 20

1. GCrich region in stem
2. single stranded U-run

Front 21

Any connection between drug resistance, antibiotics and transciptions?

Back 21

yes....topoisomerase inhibitors
ciprofloxacin-quinolone antibiotic: binds to the A subunit of bacterial DNA gyrase
novobiocin: coumarin antibiotic: inhibits bacterial DNA gyrase by binding to the ATP binding site in its B subunit

Front 22

_____have operons

Back 22

bacteria

Front 23

In eukaryotes, three RNA polymerases go to what?

Back 23

Pol I -> rRNA
Pol II -> mRNA
Pol III -> tRNA and some rRNA

Front 24

bacteria, promoter

Back 24

RNA polymerase recognizes the promoter (AT rich sequence)

Front 25

eukaryotes, promoter

Back 25

RNA polymerase does not bind promoter directly

Front 26

transcription initiation is regulated by

Back 26

transcription factors and a variety of DNA binding protein

Front 27

rifampin (rifampicin)

Back 27

broad-spectrum antibioitc used for mycobacterial infections, in immunosuppressed patients, and tb.
blocks the initiation of transciption by binding to protein pocket near active site of beta subunit of bacterial polymerase
affects bacteria

Front 28

___ mutation in beta subunit changes rifampin binding site

Back 28

point resistant bacteria in population take over

Front 29

actinomycin d

Back 29

rna polymerase inhibitor
oligopeptide tails-clamp drug to minor groove
phenoxazone ring-gets intercalated between two GC pairs
affects both bact and humans

Front 30

alpha-amanitin

Back 30

affects humans because it binds to RNA poly II

Front 31

amanita phalloides

Back 31

a mushroom that synthesizes alpha-amanitin