DNA replication

Question 1

how long are okazaki fragments in euks and proks

Answer 1

euks- 100-200, proks 1000-2000

Question 2

what nucleotides are usually rich in Oris

Answer 2

AT (also lots of short repeats)

Question 3

what do origin binding proteins recruit

Answer 3

pol III

Question 4

how do helicases unwind (what bonds get broken)

Answer 4

H bonds between bases

Question 5

Primase is a ____ dependent ____ polymerase that makes a _____ of ____ nucleotides on the ____ strand

Answer 5

DNA dependent RNA polymerase, makes RNA primer of roughly 10 nt on parent strand

Question 6

DNA pol I in proks has 3 functions

Answer 6

DNA polymerase, 3-5 exonuclease and 5-3 endonuclease

Question 7

DNA pol I is described as what and why

Answer 7

distributive, no sliding clamp and falls off often

Question 8

what is the main function of DNA pol I in proks

Answer 8

replaces RNA primers and clean up function

Question 9

DNA pol III in proks has what activity

Answer 9

3-5 exonuclease and DNA polymerase, does NOT have exonuclease aka it cannot remove RNA primers

Question 10

pol III is called “___”

Answer 10

processive- makes DNA on leading and lagging strand and is the major replicative enzyme because it has the sliding clamp

Question 11

ligase does what

Answer 11

seals okazaki fragments after pol I has replaced the RNA primers

Question 12

whats the difference between topoisomerase and gyrase (aka what is the defining characteristic of a gyrase)

Answer 12

gyrase is a type of topoisomerase that is inhibited by quinolines and mostly found in proks

Question 13

telomerase is a ___ dependent ____ polymersae that does

Answer 13

RNA dependent DNA polymerase that keeps chromosomal ends by copying their telomeric repeat sequence from an RNA template

Question 14

how does this telomerase get it to work

Answer 14

telomeres are a uniform repetitive sequence

Question 15

where is telomerase repressed and where is it expressed

Answer 15

repressed in normal somatic cells, expressed in germ line or cancer cells

Question 16

example of an endogenous and exogenous reverse transcriptase

Answer 16

endogenous= telomerase and exogenous is in retrovirus’

Question 17

what strand has the end replication problem

Answer 17

lagging

Question 18

what does DNA polymerase require to work

Answer 18

RNA primer (the 3’ OH)

Question 19

what direction is DNA polymerase making stuff

Answer 19

5-3

Question 20

how are errors corrected in DNA polymerase

Answer 20

3-5 exonuclease

Question 21

what two prokaryotic polymerases have proofreading ability

Answer 21

1 and 3

Question 22

leading strand order of events

Answer 22

1. origin binding proteins bind to origin, 2. DNA melted by helicases, 3. ssbp bind ss DNA, 4. topoisomerase relieves tension, 5. pol III elongates

Question 23

what is the difference between leading strand origin of events

Answer 23

primes comes in after topoisomerases to add RNA primers and you need ligase to synthesize all of the okazaki fragments