Chapter 11

Question 1

What is dna replication

Answer 1

Process that copies genetic material

Question 2

What are original dna strands used for

Answer 2

Templates when synthesizing new strands with identical sequences

Question 3

What does dna replication rely on

Answer 3

Complementarity of dna strands
The A T and G C rule

Question 4

What are the old and new strands of dna called

Answer 4

New strands are daughter strands
Old strands are parental strands

Question 5

What is bacterial dna replication

Answer 5

Formation of two replication forks at the origin of replication

Question 6

Where does dna synthesis begin

Answer 6

Origin of replication
Each bacterial chromosome only has one

Question 7

Which way can bacterial dna synthesize dna

Answer 7

Bidirectionally

Question 8

What are the three types of dna sequences in the oriC

Answer 8

DnaA boxes which are the sites for binding DnaA protein
AT rich regions which are the sites where dna strands separate
GATC methylation sites which help regulate dna replication

Question 9

After the DnaA proteins bind to the DnaA boxes and the strands separate at the AT rich region what does the DnaB or helix see do

Answer 9

Binds to the origin and further separates the DNA strands
It travels along the DNA in 5-3 prime direction and uses energy from ATP
Made of six subunits

Question 10

Is the daughter strand methylated directly after replication

Answer 10

No the DNA adenine methyltransferase methylates it
Initiation of replication occurs only after the dna is fully methylated

Question 11

What enzyme separates the two dna strands and how

Answer 11

DNA helicase by breaking hydrogen bonds
This creates positive supercoiling ahead of the replication fork

Question 12

What does topoisomerase or dna gyrase do

Answer 12

Travels ahead of the helicase and gets rid of the supercoils

Question 13

What is a single strand binding protein

Answer 13

Binds to separated dna strands to keep them apart

Question 14

What are rna primers synthesized by

Answer 14

Primase

Question 15

What is dna polymerase

Answer 15

Enzymes responsible for synthesizing dna

Question 16

What does dna polymerase III do

Answer 16

Synthesize a daughter strand of dna

Question 17

What does dna polymerase I

Answer 17

Removes rna primers and fills the gaps with base pairs

Question 18

What does dna ligase do

Answer 18

Links the dna backbones in the Okazaki fragments together

Question 19

What does dna polymerase I and III do versus dna polymerase II,IV, and V

Answer 19

I and III do normal replication
II, IV, and V repair and replicate damaged dna

Question 20

What are some features of dna polymerase

Answer 20

It cannot initiate dna synthesis by linking nucleotides
It needs a 3’ hydroxyl group and always adds to the 3’ end

Question 21

What is the leading strand

Answer 21

RNA primer made at the origin
DNA pol III adds nucleotides as it slides toward the replication fork

Question 22

What is the lagging strand

Answer 22

Synthesized in the 5-3 prime direction but occurs away from the replication fork
Many rna primers are required
Looped

Question 23

What are Okazaki fragments

Answer 23

Chunks of Complementary strands of dna on the lagging strand
Made by dna polymerase III

Question 24

What makes up a primosome

Answer 24

DNA helicase and primase binding to each other

Question 25

How is a replisome formed

Answer 25

Primosome associated with two dna polymerase holoenzymes

Question 26

What are the two important ter sequences

Answer 26

T1 which stops counterclockwise forks
T2 which stops clockwise forks

Question 27

When tus binds to ter sequences what happens

Answer 27

They stop the movement of the replication forks

Question 28

What are catenanes

Answer 28

Intertwines circular molecules
Separated by the action of topoisomerase II

Question 29

What does dna polymerase form bonds between

Answer 29

Innermost phosphate group of incoming deoxyribonucleoside triphosphate and the 3’ OH of the sugar of the previous deoxynucleotide