DNA Replication

Question 1

What are the 3 possible replication patterns of DNA?

Answer 1

Semiconservative replication
Conservative replication
Dispersive replication

Question 2

Semiconservative replication

Answer 2

Would produce molecules with both old and new DNA, but each molecule would contain one complete old strand and one complete new one

Question 3

Conservative replication

Answer 3

would preserve the original molecule and generate an entirely new molecule

Question 4

Dispersive replication

Answer 4

would produce two molecules with old and new DNA interspersed along each strand

Question 5

what are the 2 steps of semiconservative DNA replication?

Answer 5

double helix unwound into 2 strands

new nucleotides form complementary base pairs and covalently link together

Question 6

how does replication begin

Answer 6

binding of large protein comoplex to specific site on DNA molecule

Question 7

origin of replication

Answer 7

found on all chromosomes- pre replication complex binds

Question 8

what is the third step in DNA replication

Answer 8

DNA is unwound and replication proceeds in both directions around circle to form two replication forks

Question 9

what does DNA replication have to begin with?

Answer 9

primer- short, started strand of RNA

Question 10

what is the 5th step in DNA replication

Answer 10

DNA polymerase elongated a polynucleotide strand by covalently linking new nucleotides to preexisting strand

Question 11

what synthesizes the primer? How many nucleotides at a time?

Answer 11

primase, 1

Question 12

what happens after the primer is synthesized?

Answer 12

DNA polymerase adds nucleotides to 3’ end of primer

Question 13

after the nucleotides are added to the 3’ end of the primer, what happens?

Answer 13

RNA primer degrades and when DNA is replicated, only DNA left

Question 14

describe DNA polymerases

Answer 14

large and shaped like right hand

Question 15

how do proteins assist with DNA polymerization

Answer 15

unwind and separate DNA strands held together by hydrogen bonds and van der waals

Question 16

DNA helicase

Answer 16

uses energy from ATP hydrolysis to unwind and separate strand

Question 17

single strand binding proteins

Answer 17

bind to unwound strands to keep them from reassociating into a double helix

Question 18

DNA at replication fork

Answer 18

DNA unwinds to expose bases

Leading and lagging strands

Question 19

leading strand

Answer 19

grow continuously at 3’ end (forward)

Question 20

lagging strand

Answer 20

3’ end gets farther from fork and gap forms (backward)

Synthesized by Okazaki fragments

Question 21

DNA ligase

Answer 21

catalysts formation of bond for lagging strand

Question 22

what are the parts of DNA synthesis

Answer 22

DNA helicase, 2 polymerases, primase, ligase, proteins

Question 23

DNA polymerases are (blank)

Answer 23

processive

Question 24

processive

Answer 24

catalyze the formation of many phosphodiester linkages each time they bind to a DNA molecule

Question 25

sliding DNA clamp

Answer 25

stabalizes DNA polymerase

Question 26

telomeres

Answer 26

repetitive sequences at the ends of chromosomes

bind protein to prevent recognition of chromosome breaks

Question 27

telomerase

Answer 27

catalyzes the addition of any lost telomeric sequences in these cells