lecture 25

Question 1

What is the pathway from DNA to protein

Answer 1

replication
transcription
translation
protein

Question 2

What are the 3 differences between DNA and RNA

Answer 2

-DNA has no oxygen on the 2 prime while RNA has a hydroxide
- DNA uses the base pair Thymine instead of uracil
- RNA is more reactive due to its exposure of tis nucleotides since its single stranded

Question 3

How can RNA adopt secondary structures

Answer 3

it can bond to DNA and other RNA. the uracil doesn’t affect the Watson crick pairing

Question 4

How can RNA adopt tertiary structures

Answer 4

The short strands adopt non conventional (no Watson crick) paring as well as regular. They are more stable than the 3D model and can perform cellular function

Question 5

How and where does transcription and translation occur in Prokaryotes?

Answer 5

both occurs in the cytoplasm the same time because multiple ribosomes can work on different sections of the RNA at a time

Question 6

How and where does transcription and translation occur in Eukaryotes?

Answer 6

Transcription occurs in the nucleus from DNA to RNA
Translation occurs in the cytoplasm and its RNA to proteins since the DNA can’t leave the nucleus

Question 7

why is gene expression regulated?

Answer 7

too much of a certain protein, even an good one, can affect the organism

Question 8

In bacteria, what are the 2 factors that control the concentration of mRNA

Answer 8

• rate of syntheses and degradation of the mRNA

Question 9

for gene control in Prokaryotes, what 3 most important elements (in order)

Answer 9

• transcription initiation
• RNA turnover (nuclease degradation)
• transcription termination

Question 10

during RNA synthesis, what is used?

Answer 10

NTP not dNTPs

Question 11

What is the template strand?

Answer 11

the strand being read to make the mRNA

Question 12

wha is the coding strand?

Answer 12

the strand that is exactly the sane as the mRNA
(EXCEPT the mRNA has U but the DNA has T)

Question 13

another name for the template stand?

Answer 13

antisense

Question 14

another name for the coding strand?

Answer 14

sense

Question 15

what direction is transcription?

Answer 15

5’ to 3’

Question 16

what does downstream mean?

Answer 16

in the 3’ direction

Question 17

What does the upstream mean?

Answer 17

in the 5’ direction?

Question 18

How does the RNA polymerase know where to start?

Answer 18

it locates the -35 and -10 region and starts at the +1

Question 19

What are the -35 and -10 regions?

Answer 19

upstream regions in the promoter with specific order of nucleotides so the sigma factor can recognize it

Question 20

What are the components to the RNA polymerase

Answer 20

RNA core and sigma subunit

Question 21

what is the space between the regions and what is special about them?

Answer 21

15-17 base pairs and the region are similar amongst many promoters

Question 22

What are the 3 stages of DNA transcription into RNA

Answer 22

• initiation
• elongation
• termination

Question 23

explain initiation

Answer 23

-the RNA polymerase will go along the DNA strand until the stigma factor identifies the -35 and -10 region of the DNA strand
- the then polymerase will close around the DNA and begin unwinding it.
- Then uses 2 dNTPs as primer and begins elongation

Question 24

explain elongation

Answer 24

After 10 base pairs, the sigma factor falls off. The mRNA will be made persessively (catalyzing many times without falling off) until signalled to stop

Question 25

explain the termination sequence

Answer 25

there’s Rho-dependent and Rho-independent to signal termination

Question 26

Rho-independant termination

Answer 26

• it creates an “hairpin” shape by have a GC rich sequence that will bind to itself so it doesn’t bind to the DNA template
• then multiple U’s will be put after the Hairpin so the hairpin section will fall off the coding strand

Question 27

Rho-dependant termination

Answer 27

the rho protein will come and identify a CA- rich region on the RNA strand called the RUT site then perform ATP hydrolyzes to move toward the end of the RNA strand to unzip it from the template strand.