Module 2 Initiation + Elongation

Question 1

DNA replication is a sequence of repeated ____ ( _____) reactions linking nucleotide monomers into a DNA polymer.

DNA replication has 3 parts:

Answer 1

Condensation (dehydration synthesis)

Initiatioin
Elongation
Termination

Question 2

INITIATION:

DNA synthesis starts at one or more ____ which are DNA sequences targeted by ____

These are usually rich in ____ and ____ bases because the TWO Hydrogen bonds they have together require less energy

Answer 2

Origins of replication
Initiator Proteins

Adenine
Thymine

Question 3

INITIATION:

_______ Region of DNA served by one replication origin

____ control the initiation of DNA replication by directing assembly of the replication machinery

Three common features of Replication Origins

1 Unique DNA segments that contain multiple _____ sequences

2 These sequences are recognized by _____

3 Origin regions usually contain an ____

Answer 3

Replicon

Origin-binding proteins

1) Short Repeated Sequences

2) Multimericorigin-bindding proteins

3) AT-rich stretch

Question 4

INITIATION:

Three types of replication origins:

Answer 4

E. coli oriC

yeast autonomously replicating sequences (ARS)

simian virus (SV40) Origin

Question 5

______

DNA nucleotides are then added to the ____ of primers by a _____.

Answer 5

Elongation

3’ end

DNA polymerase

Question 6

What allows the lagging strand to make fragments? The creation of a ____ allowing the enzyme to add nucleotides at a 3-hydroxyl end of a growing segment.

These create okazaki fragments. There are about ____ to ___ nucleotides in a fragment in e coli but ____ to ____ in eukaryotes.

Synthesis occur at the same rate

DNA polymerase can’t start a new chain as they need a ____

RNA Polymerase can start a new chain.

Answer 6

Trombone structure

1000 to 2000 e coli

100-200 eukaroytes

polynucleotide primer

Question 7

_____
The enzyme that is responsible for the polymerization of nucleotides to nucleic acid (DNA) during the elongation phase

The first was discovered in E. coli by ____ for which he received the ____. It was specifically the ____ kind.

It was _____, the son who found out two more DNA polymerase

Answer 7

DNA polymerase

Arthur Kornberg
1959 Nobel Prize in Chemistry

DNA Pol I

Thomas Kornberg

Question 8

E. Coli DNA Pol I has 3 enzymatic activities

5’ -> 3’

3’ -> 5’

5’ -> 3’

Answer 8

5’ -> 3’
Polymerization

3’ -> 5’
Exonuclease Proofreading

5’ -> 3’
Exonuclease, edit sections of damaged DNA

Question 9

DNA Pol III is highly ____

DNA Pol I is ____

______ continuous synthesis without dissociation from template, leading strand

______ dissociate from the template after each nucleotide addition, lagging strand

Answer 9

DNA Pol III Processive
DNA Pol I Distributive

Processive

Distributive

Question 10

DNA Polymerase I

DNA Polymerase II

DNA Polymerase III

DNA POlymerase IV

DNA Polymerase V

Answer 10

Removes primers

DNA repair, restarts replication, halts synthesis

Elongates DNA

DNA Repair

DNA Repair, translesion DNA synthesis

Question 11

Mammalian cells:

_____
Initiation of nuclear DNA synthesis and DNA repair, primase activity

_____
DNA repair and reccombination of nuclear DNA

_____
Replication and repair of mitochondrial DNA

______
Leading and lagging strand synthesis of nuclear DNA

______
Solely Leading strand synthesis

Answer 11

a

B+

y

o

E

Question 12

Detection of replication errors and corrections (3):

Answer 12

Extension error

Proofreading
-hydrolysis of nucleotide

Extension