Week 2 Lecture 2

Front 1

what is a replicon

Back 1

the unit of DNA in which an individual act of replication occurs is called a replicon

Front 2

what is a licensing factor

Back 2

a factor located in the nucleus and necessary for replication that is inactivated or destroyed after one round of replication

Front 3

name some licensing factors

Back 3

1. MCM proteins

2. Cdc6 and Cdt1

Front 4

describe licensing fator MCM

Back 4

it is a DNA helicase - seperates strands on either side of an ORC complex

-hexameric complex

-final licensing factor

Front 5

what is nick translation

Back 5

replaces part of a preexisting strand of duplex DNA with newly synthesised material

Front 6

what is processivity

Back 6

ability of an enzyme to perform multiple catalytic cycles with a single template strand instead of disassociating after each cycle.

-DNA polymerase requires additional factors for processivity

Front 7

what is semi-discontinuous repliaction

Back 7

mode of replication in which one new strand is synthesised continuously while the other is synthesised discontinuously

Front 8

what does helicase do

Back 8

seperates the strands of DNA using energy provided by hydrolysis of ATP

Front 9

what does replication factor A (RFA) do

Back 9

a single-stranded binding protein that is required to maintain the seperated strands

Front 10

what is requires to initiate DNA synthesis

Back 10

3'OH priming end

Front 11

what ways can priming end be provided by

Back 11

RNA primer, a nick in DNA, priming protein

Front 12

what is primase

Back 12

a type of RNA polymerase that synthesises short sequences of RNA or DNA that will be used as primers for DNA synthesis

Front 13

what does the priming of replication on double stranded DNA require

Back 13

SSB (RPA) and primase

Front 14

what is the helicase required to unwind DNA for replication in E.coli

Back 14

DnaB

Front 15

what is the helicase required to unwind DNA for replication in eukaryotes

Back 15

MCM

Front 16

what is the priming technique used in E.coli

Back 16

DnaG

Front 17

what is the priming technique required in eukaroyotes

Back 17

Pol alpha/ primase

Front 18

in E.coli what catalytic subunit required for the synthesis of the leading and lagging strand

Back 18

DnaE, on the other hand diff catalytic subunits required for the leading and lagging strand in eukaryotes

Front 19

what does the DNA dependent polymerase alpha/primase do

Back 19

it initiates or primes the synthesis of both DNA strands.

synthesises RNA on lagging strand

synthesises DNA on leading strand

Front 20

which strand does DNA polymerase epsilon elongate

Back 20

leading strand

Front 21

which strand does DNA polymerase delta elongate

Back 21

lagging strand

Front 22

what is PCNA

Back 22

-proliferating cell nuclear antigen

-sliding clamp

-helps in processivity of both polymerases epsilon and delta

Front 23

what is the clamp loader? and what does it do?

Back 23

clamp loader - RFC in eukaryotes

-it places the processivity subunits on DNA (polymerase epsilon on leading strand and polymerase delta on lagging strand)

-increases processivity

-uses ATP to associate with PCNA and attach to DNA

Front 24

name and describe telomere binding proteins

Back 24

Pot 1 - protection of telomeres 1 - binds to ddDNA - caps the end of telomeres

TRF1 - binds to dsDNA - recognizes specific telomeric DNA sequences that bind to the dsDNA region

TRF2 - binds to dsDNA-allows the 3'extreme single stranded end of the telomere to fold back and form a T-loop