DNA replication

Question 1

dna wys to replicate

Answer 1

• conservative, two strans stay together and two new made
• semi conservvative
• dispersive. bits of parent in daughter

*proved by 14N and 15N crap

Question 2

dna pol I

Answer 2

• one chain w weight of 110,000
• needs a primer of single strange dna or rna w free 3’ OH (datp, dttp, dctp, dgtp)

activities

1) dna replicase
2) exonuclease and proofreader (1 at a time)
3) also remove primer

Question 3

nearest neighbor base frequenncy analysis

Answer 3

• dna is complimentary/ antiparallel
• add bases, use an exonuclease to cut it, then determine the radioactivity to find % of pairs
• apc= gpt NOT apg =tpc

Question 4

DNA pol III

Answer 4

in vivo in bac

• does 5/ to 3’
• good at low temp??

Question 5

okazaki

Answer 5

• endonuclease makes a nick
• primase ads primer
• ligase makes last phospho bond
• synthesize 5’ to 3’

Question 6

how to relieve strain on dna

Answer 6

• gyrase which is topoisomerase

- helicase unwinds dna and binding proteins keep it apart

Question 7

modify dna for self id

Answer 7

• epigenetics like adding methl to prevent nuclease attack

Question 8

repair of dna

Answer 8

• thymine dimer
• involves pol I and II
  1) endo nuclease makes cut
  2) exonuclease clips of damage
  3) polymerase
  4) ligase

Question 9

sediment coefficient

Answer 9

trna is 4s

- higher means larger

Question 10

rrna

Answer 10

• make up ribosome

- support structure during protein synth and make peptide bonds

Question 11

small rna

Answer 11

• small rna play regulatory role in transcription

Question 12

dna rna hybrid

Answer 12

when you heat them, realize that rna is denser than dna

- so when they cool, they make hybdrid which is more dense than dna alone

Question 13

dna dependent rna pol

Answer 13

• nucleotides added to 3’ end of rna
• needs dna template but no primer
• only one strand made

Question 14

rna synthesis steps

Answer 14

1) binding: pol binds dna. 1st nuc iS PURINE
2) initiation: 1st bond
3) elongation
4) termination: release of rna

Question 15

rna pol subunit B

Answer 15

dna binding, binds rifampicin, active site

Question 16

rna pol subunit B’

Answer 16

dna binding

Question 17

rna pol subunit a

Answer 17

template site selection

Question 18

rna pol core enzyme

Answer 18

• a bb’ portion

- transcribes dna randomly

Question 19

rna pol holoenzyme

Answer 19

• holoenzyme is with sigma subunit too

- results in selective transcription at promoter regions

Question 20

promoter region

Answer 20

• initiation complex starts at promoter region, upstream from gene (TATA box or palindrome)
• also dna can be weird shaped in this region (called cruciform)

Question 21

rifampicin

Answer 21

• drug inhibits formation of first bond

- only in prokarya

Question 22

rho

Answer 22

• termination factor