Ch. 11

Question 1

When DNA is replicated, what is the model of replication?

Answer 1

Semiconservative, 1 parent strand 1 daughter strand

Question 2

How did Meselson and Stahl investigate semiconservative DNA replication?

Answer 2

Experimentally distinguished parent strands by analyzing light and heavy nitrogen

Question 3

For Meselson and Sahls investigation, what were the results after the first generation?

Answer 3

DNA was half-heavy, consistent with both semiconservative and dispersive models

Question 4

For Melselson and Sahls investigation where were the results after the second generation?

Answer 4

DNA was either light or heavy consistent only with the semiconservative model

Question 5

For bacteria where does DNA replication begin?

Answer 5

Origin of replication

Question 6

In bacterial DNA replication how does the replication proceed?

Answer 6

Bidirectionally around the bacterial chromosome

Question 7

How would you name the origin of replication of E. coli

Answer 7

oriC

Question 8

For oriC what is a DnaA box

Answer 8

sites for the binding of DnaA protein

Question 9

For oriC what is AT-rich regions

Answer 9

sites where the DNA strands separate

Question 10

For oriC what is GATC methylation sites

Answer 10

sites that help to regulate DNA
replication

Question 11

What does DnaB/helicase do in oriC

Answer 11

Further separates the DNA strands, travels in 5’ to 3’ direction and uses ATP

Question 12

DNA adenine methyltransferase does what to the DNA strands?

Answer 12

Methylates the A on both strands

Question 13

Why is DNA adenine methyltransferase (Dam) important for regulation?

Answer 13

prevents second replication from proceeding too soon

Question 14

What does topoisomerase do in DNA replication?

Answer 14

Travels ahead of DNA helicase and alleviates supercoiled DNA

Question 15

What binds to separated DNA strands to keep them apart?

Answer 15

Single-strand binding proteins

Question 16

What synthesizes the short RNA primers for DNA replication

Answer 16

primase

Question 17

What doe the RNA primers do in DNA replication

Answer 17

Prime DNA synthesis with a few RNA base pairs 10-12 nucleotides in length

Question 18

How many primers does the leading strand have?

Answer 18

1

Question 19

How many primers does the lagging strand have?

Answer 19

Multiple

Question 20

What enzyme synthesizes DNA after it has been primed in bacterial DNA replication

Answer 20

DNA polymerase III

Question 21

What DNA polymerase excises the RNA primers in bacterial DNA replication

Answer 21

DNA polymerase I

Question 22

What enzyme links the DNA backbones together in the Ozaki fragments on the lagging strand?

Answer 22

Ligase

Question 23

Which direction is DNA synthesized?

Answer 23

5’ to 3’

Question 24

DNA helicase and primase are physically bind to each other to form a complex called the ________

Answer 24

primosome

Question 25

What does a primosome do?

Answer 25

Coordinates the actions of helicase and primase

Question 26

The primosome is physically associated with two DNA polymerase holoenzymes to form the _______

Answer 26

replisome

Question 27

What are some characteristics of eukaryotic DNA replication

Answer 27

1. large linear chromosomes 2. chromatin is tightly packed within nucleosomes 3. more complicated cell cycle regulation

Question 28

Do eukaryotes have multiple origins of replication?

Answer 28

Yes

Question 29

How long are the telomeric overhangs in eukaryotic DNA replication

Answer 29

12-16 nucelotides

Question 30

Eukaryotic telomere overhangs typically consist of what two nucleotides?

Answer 30

Thymine and guanine

Question 31

At the 3' ends of eukaryotic linear chromosome, can the end of the strand be replicated? What enzyme solves with problem?

Answer 31

No enzyme telomerase

Question 32

What si the enzyme action of telomerase

Answer 32

1. binding 2. polymerization 3. translocation