Exam 1 part 2 Flashcards Preview

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Flashcards in Exam 1 part 2 Deck (18)
1

Conservative replication model

one old and one brand new helix

2

Semiconservative replication model

one strand is parent and other is novel

3

Dispersive replication model

parent and new are intermixed

4

Initiation of replication

1. replicator sequence is denatured by initiator proteins to form a replication bubble
2. helicase loaded onto the DNA
3. Helicase recruits primase
4. primase synthesizes a short primer

5

Semidiscontinuous replication

1. SSB proteins bind to the ssDNA in the fork
2. polymermase III adds nucelotides ONLY in the 5' to 3' direction
3. DNA gyrase relaxes the tension ahead of the replication fork

6

Joining of the Okazaki fragments

1. Polymerase I digests RNA primer ahead of it using its 5' to 3' exonuclease activity and replaces it with dNTBs using its 5' to 3' polymerase activity
2. DNA liagase seals the nick bt adjacent fragments

7

Polymerase III

adds dNTPs from an RNA primer in 5' to 3' direction

8

Polymerase I

digests RNA primer using 5' to 3' exonuclease activity
Replaces RNA primer with dNTPs using its 5' to 3' polyermase activity

9

DNA ligase

seals the nick between adjacent fragments

10

Primer from DNA pol I

Okazaki fragment

11

fidelity

accuracy of polymerase -how many mistakes
versus porcessivity

12

Processivity

how long polymerase can stay on the strand -how many nucleotides it can add
-if it has to correct mistake, it can't add as many
-almost always adds the correct complimentary base pair
1/1mil is incorrect

13

Polymerase ____ has both 5' to 3' AND 3' to 5' exonuclease activity

Polymerase I

14

Replication in eukaryotes

chromosomes are linear and bigger
Many origins per chromosome
15 polymerases (many participate in repaire)
DNA is packed as it is synthesized (wrapped around histones as it comes off rep. bubble)

15

Replicon

unit of measurement bt bubble fusion and one origin of replication

16

Telomeres

tandemly repeated
Added by telomerase

17

Telomerase

Adds telomeres
Reverse transcriptase
complex of protein (synthesizes) and (template)
Makes the 3' overhang longer to prevent gene loss and retain chromosome size

18

Reverse transcriptase

makes DNA from RNA template
Telomerase