DNA replication

Question 1

Ends of DNA strands

Answer 1

5’ to 3’ ends

Question 2

4 Nucleotides divided into 2 classes

Answer 2

Purines: Adenine and Guanine (Pure as Gold)
Pyrimidines: Cytosine & Thymine

Question 3

Base Pairs are

Answer 3

A-T, G-C

Question 4

What bonds hole the nucleotide pairs together?

Answer 4

Hydrogen Bonds

G&C–> 3 H-bonds, A&T–> 2 H-bonds

Question 5

Which way is assembled

Which way read

Answer 5

Read 3’ to 5’

Assembled 5’ to 3’

Question 6

DNA replication begins…

Answer 6

At origin of replication

Question 7

DNA helicase

Answer 7

unwinds DNA stands to produce a replication fork

Question 8

Single Stranded Binding Proteins (SSBs)

Answer 8

stabilize DNA to prevent strands from reforming

Question 9

Topoisomerase

Answer 9

Prevents strands from over twisting

Question 10

Primase

Answer 10

Creates RNA primer to initiate a new DNA strand in a 5’ to 3’ direction

Question 11

DNA polymerase

Answer 11

extends primer and makes the strand 5’ to 3’

Question 12

Leading Strand

Answer 12

Continuous

Question 13

Lagging stand

Answer 13

Discontinuous–> creates Okasaki Fragments

Question 14

Sliding clamp

Answer 14

tethers DNA pol III to the DNA template

Question 15

DNA pol I

Answer 15

removes RNA primer, adds nucleotides

Question 16

DNA Ligase

Answer 16

Seals nicks

Question 17

Telomeres and Telomerase

Answer 17

Prevents loss of important sequences (Shortening).

Uses its own RNA template, RNA primer laid down, DNA Pol fills in sequence

Question 18

Polymerase Proofreading

Answer 18

DNA polymerase reads, proofreads and corrects mismatch bases

Question 19

How are mismatched base pairs seen?

Answer 19

they distort the helix structure so recognized and excised. Polymerase fills the gap and ligase seals the nick

Question 20

What is the function of telomerase

Answer 20

Prevents chromosome shortening