06b: RNA

Question 1

(DNA/RNA) is the master copy and (DNA/RNA) is the working copy.

Answer 1

DNA; RNA

Question 2

(DNA/RNA) is carefully reproduced and stable.

Answer 2

DNA

Question 3

(DNA/RNA) is constantly synthesized, used, degraded.

Answer 3

RNA

Question 4

The processes of transcription and translation are (X) in prok and (Y) in euk.

Answer 4

X = closely coupled

Y = spatially and temporally separate

Question 5

T/F: the lengths of DNA and RNA are similar.

Answer 5

False - RNA shorter

Question 6

T/F: RNA is always single-stranded.

Answer 6

True

Question 7

(DNA/RNA/both/neither) can form secondary loop and stem structures.

Answer 7

RNA only (ex: tRNA)

Question 8

Abundance of (X) RNA is the greatest. And of (Y) RNA is the least.

Answer 8

X = rRNA

Y = mRNA

Question 9

The unit that defines RNA size (ex:20S) is related to the (X) of the molecule.

Answer 9

X = size and shape

Question 10

In transcription, DNA is read in which direction? And RNA is synthesized in which direction?

Answer 10

Read: 3’ to 5’

Synthesis: 5’ to 3’

Question 11

Which enzyme creates primer for transcription?

Answer 11

NO PRIMER NEEDED

Question 12

The coding strand is the (X) strand.

Answer 12

X = sense

Question 13

The non-coding strand is the (X) strand.

Answer 13

X = template

Question 14

Bacterial RNA pol has which subunits in core enzyme?

Answer 14

Alpha (2 of them), beta, beta(‘)

Question 15

RNA pol in bacteria: holoenzyme has which subunits?

Answer 15

Alpha (2 of them), beta, beta(‘), and sigma

Question 16

Which subunit in prok RNA pol has the catalytic site?

Answer 16

Beta

Question 17

Which subunit in prok RNA pol binds the DNA template?

Answer 17

Beta(‘)

Question 18

Sigma subunit in prok RNA pol has which function?

Answer 18

Recognizes promoter regions (needed for appropriate initiation)

Question 19

T/F: in genome, either DNA strand can be the template.

Answer 19

True

Question 20

Which steps in transcription are catalyzed by RNA pol?

Answer 20

All (initiation, elongation, termination)

Question 21

The prok promoter region sequences are written on the (X) strand.

Answer 21

X = sense (coding)

Question 22

Once RNA pol binds DNA, an (open/closed)-promoter complex forms.

Answer 22

Closed-promoter complex first, then open-promoter complex

Question 23

Beta subunit on RNA pol has (X) sites for:

Answer 23

X = 2 NT binding sites:

1. For 5’ purine
2. For all subsequent NTPs

Question 24

First base in transcription is almost always:

Answer 24

Purine-5’-triphosphate

Question 25

How long does sigma subunit stay bound during transcription?

Answer 25

Released as pol starts to proceed down template

Question 26

How many bp of DNA is unwound in open-promoter complex during transcription?

Answer 26

About 12 bp

Question 27

During transcription, the RNA-DNA hybrid is about (X) bases long.

Answer 27

X = 8

Question 28

What are the requirements for transcription termination that is (X)-independent?

Answer 28

X = Rho

1. Must be GC-rich palindrome
2. Must be followed by UUUUs

Question 29

GC-rich palindrome during (X) forms:

Answer 29

X = Rho-independent transcription termination

Forms hairpin loop

Question 30

String of UUUs during (X) significant because:

Answer 30

X = Rho-independent transcription termination

Form weak AU bonds that can easily break to release RNA transcript

Question 31

Majority of transcription termination cases are Rho-(dependent/independent).

Answer 31

Independent

Question 32

What is Rho?

Answer 32

Large protein that’s a helicase and an ATPase

Question 33

List steps of Rho-dependent termination.

Answer 33

1. Rho binds DNA
2. Hydrolyzes ATP and moves down DNA-RNA hybrid (5’ to 3’)
3. Catches up with RNA pol
4. Helicase unwinds hybrid, releasing RNA

Question 34

Rifampicin is used to treat (X). What’s its mechanism?

Answer 34

X = TB

Inhibits formation of first phosphodiester bond in transcription initiation

Question 35

A mutation in which subunit of M. tuberculosis RNA pol would lead to rifampicin-resistant TB?

Answer 35

Beta subunit

Question 36

What are the key differences in euk transcription, compared to prok?

Answer 36

1. Three different RNA pols
2. No sigma subunit
3. Pol-protein interactions, NOT pol-DNA interactions, govern initiation

Question 37

Which RNA pol in euk transcribes mRNA?

Answer 37

Pol 2

Question 38

In euk, the core promoter region is composed of which elements?

Answer 38

1. Basal (-25)
2. Constitutive (-110)
3. Inducible (-150)

Question 39

Basal promoter region function

Answer 39

Determines start site

Question 40

Constitutive promoter region function

Answer 40

Determines transcription rate (based on number and order of these sequences)

Question 41

Inducible promoter region function

Answer 41

Determine specificity of transcription (ex: environment, hormones bind, etc)

Question 42

Euk transcription initiated after which key event?

Answer 42

Phosphorylation of RNA pol 2 by TFIIH (kinase)

Question 43

Euk transcription terminated after which key event?

Answer 43

Dephosphorylation

Question 44

Difference between inducible and constitutive.

Answer 44

Inducible: either on or off, depending on presence of stimulus

Constitutive: always made, but at different rates

Question 45

T/F: genes transcribed by all euk RNA pol have significant regulation.

Answer 45

False - RNA pol 1 and 3 have minimal regulation

Question 46

Alpha-amanitin affects (euk/prok) by:

Answer 46

Euk only;

Inhibits RNA pol 2 (and pol 3 a tiny bit), so no protein synthesis (liver failure, death)