DNA Replication

Question 1

What is DNA replication?

Answer 1

MAking a copy of DNA

Question 2

Why do we need DNA replication?

Answer 2

Cell reproduction

Question 3

Watson and Crick discovery suggested what?

Answer 3

Base pairing suggested possible copying mechanism

Question 4

What does it mean to be semiconcervative?

Answer 4

Half of new molecule comes from the parent DNA and the other half is synthesized

Question 5

What are chromosomes?

Answer 5

Condensed DNA

Question 6

What are the two types of chromosomes?

Answer 6

1. Linear

2. Circular

Question 7

What are the bonds between nucleotides?

Answer 7

H-bonds

Question 8

How many chromosomes are in E. coli?

Answer 8

Single circular chromosome

Question 9

What is the shape of a human chromosome? How many do they have?

Answer 9

Linear; 23 chromosome pairs

Question 10

What is the origin of replication?

Answer 10

Where replication starts

Question 11

What is the replication “bubble”?

Answer 11

The bubble created by splitting the H-bonds between nucleotides

Question 12

What does it mean to have bidirectional replication?

Answer 12

Replication done on both sides of the fork

Question 13

Where does new DNA attach to 3’ end of a polynucleotide?

Answer 13

Hydroxyl group of the 3’ C (2 PO4) are lost in process

Question 14

What kind of reaction creates polynucleotides?

Answer 14

Dehydration Reaction

Question 15

What kind of bond is created by the dehydration reaction?

Answer 15

Covalent phosphodiester bonds

Question 16

New DNA strands elongate ONLY in _’ to _’ direction.

Answer 16

5’ to 3’

Question 17

How do you determine if the strand is the leading or lagging strand?

Answer 17

Leading- toward fork

Lagging- away from fork

Question 18

KNOW THE STEPS OF LAGGING AND LEADING DNA REPLICATION.

Answer 18

YES SIR

Question 19

What is the role of helicase?

Answer 19

Unwind parental double helix at replication forks

Question 20

What is the role of single strand binding protein?

Answer 20

Binds to and stabilizes single-stranded DNA until is it used as a template

Question 21

What is the role of topoisomerase?

Answer 21

Relieves overwinding strain ahead of replication forks by breaking, swiveling, and rejoining DNA

Question 22

What is the role of primerase?

Answer 22

Synthesizes an RNA primer at 5’ end leading strand and at 5’ end of each Okazaki fragment lagging strand

Question 23

What is the role of DNA polymerase III?

Answer 23

Using parental DNA as a template, synthesizes new DNA strand by adding nucleotides to an RNA primer or a preexisting DNA strand

Question 24

What is the role of DNA polymerase I?

Answer 24

Removes RNA nucleotides of primer from 5’ end and replaces them with DNA nucleotides added to 3’ end of adjacent fragment

Question 25

What is the role of DNA ligase?

Answer 25

Joins Okazaki fragments of lagging strand; on leading strand, joins 3’ end of DNA that replaces primer at reset of leading strand DNA.

Question 26

Explain the “trombone” model of the DNA Replication Complex.

Answer 26

The proteins are not the moving part of this process. The DNA will move through the proteins as the replication process progresses

Question 27

What are Okazaki fragments?

Answer 27

RNA/DNA fragments created in the lagging strand of DNA replication