Exam 3: DNA Replication

Question 1

Conservative replication 1st replication

Answer 1

1 stand OG, 1 strand new

Question 2

Conservative replication 2nd replication

Answer 2

1 stand OG, 3 strand new

Question 3

Dispersive replication 1st replication

Answer 3

2 strands that are 1/2 new 1/2 OG

Question 4

Semiconservative replication 1st replication

Answer 4

2 strands that are 1/2 new 1/2 OG

Question 5

Dispersive replication 2nd replication

Answer 5

4 strands thast are 1/2 new 1/2 OG

Question 6

Semiconservative replication 2nd replication

Answer 6

2 strands all new, 2 strands 1/2 new 1/2 OG

Question 7

ARSs

Answer 7

Autonomously Replicating Sequences typically found at AT-rich regions due to only being held together with 2 H bonds opposed to 3 H bonds between C and G

Question 8

ORC

Answer 8

binds to roigin and sepereates strands of DNA to initiate replication

Question 9

MCM2+7 + co-factors

Answer 9

helicase complex that unwinds DNA at replcation forks

Question 10

single-stranded binding proteins

Answer 10

attatched to single-strnaded DNA and prevent secodnary structures from forming

Question 11

topoisomerase

Answer 11

moves ahead of the replication fork, making and resealing breaks in the double helical DNA to release the torque that builds up as a result of unwinding at the replication fork

Question 12

DNA polymerase a

Answer 12

synthesies a short RNA primer to provide a 3’ -OH group for the attatchement of DNA nucleotides

Question 13

DNA polymerase d and e

Answer 13

elongates a new nucleotide strand for the 3’ end

Question 14

RNase and DNA polyase a

Answer 14

removes RNA primers and replaces them with DNA

Question 15

DNA ligase

Answer 15

joins Okazaki fragments by sealing breaks in the sugar-phosphate backbone of the newly sythesized DNA

Question 16

Replication direction

Answer 16

5’ to 3’

Question 17

Proofreading

Answer 17

DNA polymerase has exonuclease activity and can delete and replace incrorect nucleotides

Question 18

Types of gene mutations

Answer 18

base substitutions, insertion, and deletions

Question 19

types of base substitutions

Answer 19

transition and tranversion

Question 20

types of inversions and deletions

Answer 20

frameshift, in-frame insertion and deletions

Question 21

transition

Answer 21

purine for purine (A and G) or pyrimidine for pyrimidine (C T or U)

Question 22

forward mutation

Answer 22

wild type to mutant

Question 23

reverse mutation

Answer 23

mutant to wild type

Question 24

missnese mutation

Answer 24

amino acid to different amino acid

Question 25

nonsense mutation

Answer 25

sense codon to nonsense codon

Question 26

silent mutation

Answer 26

codon to synonomois codon

Question 27

neutral mutation

Answer 27

no change in function

Question 28

mutations related to aging

Answer 28

spontaneous replication errors and spontaneupos chemical changes

Question 29

can make mutations more likley but are still random

Answer 29

radiation and chemciually induced mutations

Question 30

How do mutations occur?

Answer 30

ss rbeaks in DNA backbone, cross-lined thymione bases, missing bases, bulky side gorup attached to base, ds break in DNA backbone

Question 31

Spontaneous replicqtion error

Answer 31

mispairing due to wobble can become incorporated and then replciated becoming a replication error

Question 32

Spontaneous chemical error

Answer 32

deamination (-NH2) alters DNA bases (C to U)

Question 33

Chemically induced mutations

Answer 33

5-bromouracil resembles thymine and may be incoporated into DNA in place of thymine and may pair with guanine due to wobble

Question 34

What does radiation and UV light cause?

Answer 34

pyrimidine dimer which is two thymine base paired together - cell division is inhibited

Question 35

end replication problem

Answer 35

after last RNA primer is removed the polymerase cannot add any more nlucleotides due to 5' end having no free -OH group