Lecture Nov 25 (DNA Replication pt 1)

Question 1

How is cAMP made?

Answer 1

cyclic AMP, made from ATP.
Enzyme gets rid of 2 phosphates on ATP

Question 2

DNA Replication

Question 3

How does DNA replication start in Ecoli? What sequence does DNA-A bind to in replication?

Answer 3

DNA-A binds to E.coli OriC
TTATCCACA (happens 4 times) and AT rich region

Question 4

What makes up the OriC?

Answer 4

the TTATCCACA (x4) and AT rich region.

Question 5

In DNA Replication, how does initiation occur?

Answer 5

1. DNA A binds to TTATCCACA sequence and opens up DNA at AT-rich sequence
2. DNA B is opened up by DNA C and attached to the DNA strand
3. DNA G (primase) binds to DNA B
4. DNA C dissasociates and DnaB starts to move down ssDNA in 5’ to 3’ direction

Question 6

What does DNA B do?

Answer 6

The helicase

Question 7

What does DnaC do?

Answer 7

Helicase loader
Puts DNA B on to DNA. Opens DNA B so that it can insert the DNA strand

Note: DNA B cant move unless DNA C is off

Question 8

What does DNA G do?

Answer 8

Puts down RNA primers

Question 9

What direction does DNAB move?

Answer 9

towards 3’ (5’ to 3’)

Question 10

Is DNAB attached to lagging or leading strand?

Answer 10

Lagging

Question 11

What is a replisome

Answer 11

like large unit of all the parts involved in replication

Question 12

Parts of the replisome

Answer 12

• DnaB
• DnaG
• DNA polymerase III
• β-clamp
• clamp loader
• SSB
• template DNA and RNA primer

Question 13

Parts of DNA Polymerase 3

Answer 13

ATE!!
Alpha
Theta
Epsilon

Question 14

What does the theta subunit of DNA Polymerase 3 do?

Answer 14

Stimulates the epsilon subunit

Question 15

What does the epsilon subunit do?

Answer 15

3’ to 5’ exonuclease, removes nucleotides
in 3’ to 5’ direction, used for proofreading

Question 16

What does the alpha subunit do?

Answer 16

5’ to 3’ polymerase, the major catalytic
function of a DNA polymerase

Question 17

What does the Beta clamp do?

Answer 17

Binds to the ssDNA AND β-clamp locates behind DNA polymerase III

Question 18

2 types of transcription factors?

Answer 18

Transcription activators and repressors

Question 19

What is positive regulation

Answer 19

When a transcription activator helps increase the rate of transcription

Question 20

What id negative regulation

Answer 20

When a transcription repressor is used

Question 21

Whats the difference between glucose and galactose?

Answer 21

Both have the same chemical formula, but galactose has OH group on 4th carbon pointing up

Question 22

What is the purpose of cAMP?

Answer 22

Binds to CAP so that it can bind to the DNA and let RNA polymerase transcribe