DNA Replication

Question 1

What is DNA replication?

Answer 1

Semiconservative

Question 2

Where does all DNA replication start?

Answer 2

at a Replication Origin

Question 3

What is a Replicon

Answer 3

Unit that is replicated together

Question 4

What is Bidirectional Replication

Answer 4

When DNA can replicate in both directions from the replication origin

Question 5

Which type of semiconservative replication has bidirectional replication?

Answer 5

Theta replication

Question 6

What types of replication have a circular DNA template?

Answer 6

Theta and Rolling Circle

Question 7

What replication model has breakage of nucleotide strand?

Answer 7

Rolling Circle

Question 8

Which type of replication has many numbers of replicons?

Answer 8

Linear eukaryotic

Question 9

Which type of replication is unidirectional?

Answer 9

Rolling Circle

Question 10

Which type of replication has the product of two circular molecules?

Answer 10

Theta replication

Question 11

Which type of replication has multiple circular DNA molecules?

Answer 11

Rolling Circle

Question 12

Which type of replication has the product of two linear DNA molecules?

Answer 12

Linear Eukaryotic

Question 13

What is DNA polymerase III in E.coli?

Answer 13

• Responsible for most DNA synthesis
• Responsible for adding nucleotides to most of the genome
• Proofreads with 3’-5’ exonuclease activity

Question 14

What is DNA polymerase I in E.coli?

Answer 14

• 5’-3’ exonuclease activity to remove RNA primers
• Proofreads with 3’-5’ exonuclease activity

Question 15

What does 5’ to 3’ polymerase activity mean?

Answer 15

As polymerase adds DNA to a newly synthesized strand; it will add nucleotides to the 3’ end. So the chain will grow 5’ to 3’

Question 16

What does 3’ to 5’ exonuclease activity mean?

Answer 16

You’re backing up / You’re removing part of the DNA you just added

Question 17

What does 5’ to 3’ exonuclease activity mean?

Answer 17

You are cutting out DNA ahead

Question 18

Describe the function of the protein if the DNA codon sequence is NOT mutated

Answer 18

In Normal and High temps, the protein will have normal function

Question 19

Describe the function of the protein if the DNA codon sequence is mutated

Answer 19

In Normal temps, the protein has normal function.
In High temps, the protein has an altered function.

Question 20

Define the Initiator protein (DnaA)

Answer 20

Initiator protein (DnaA) binds to the origin of replication causing local unwinding and a short stretch of single-stranded DNA.

Question 21

DNA helicase

Answer 21

attaches at the replication fork and breaks the H-bonds that hold the DNA together

Question 22

SSB (single-stranded binding proteins)

Answer 22

Coat single-stranded DNA to protect it, stabilize it, and prevent double-stranded DNA (hairpins)

Question 23

Gyrase

Answer 23

a topoisomerase that relieves supercoiling ahead of replication fork

Question 24

What is primase in replication?

Answer 24

synthesizes short RNA primers to allow DNA synthesis to begin

Question 25

What is the primosome?

Answer 25

Helicase and primase

Question 26

What makes eukaryotic and prokaryotic replication different?

Answer 26

Eukaryotic replication involves: - Multiple origins of replication - Replication of telomeres - Linear chromosomes formed - Nucleosome assembly follows replication - Many different DNA polymerases -Origin must be licensed or approved for replication to occur.

Question 27

Why is replication at the end of linear chromosomes (telomeres) problematic?

Answer 27

DNA replication would leave gaps at the 5' end of the strand where DNA Pol 3 can't add anything, and the chromosome would shorten each time the cell divides

Question 28

How does telomerase accomplish replication of telomeres?

Answer 28

Telomerase contains RNA which it uses to make several repeats of DNA to extend the 3' end of the telomere.

Question 29

How is the RNA used in a telomerase?

Answer 29

The RNA is used as a template for DNA synthesis (reverse transcription). After several nucleotides are added, telomerase moves along the DNA and more nucleotides are added. Eventually telomerase is removed.