DNA Replication

Question 1

T/F: Coupled transcription and translation occurs in both

eukaryotes and prokaryotes.

Answer 1

False, only in prokaryotes

Question 2

Importance of DNA Replication

Answer 2

for the genetic program to be duplicated and be passed on to offsprings

Question 3

major enzyme involved in DNA Replication

Answer 3

DNA Polymerase III

Question 4

3 major steps in DNA Replication

Answer 4

Initiation, Elongation, Termination

Question 5

Origin of DNA Replication in Bacteria

Answer 5

OriC locus

Question 6

In DNA Replication occurs in the which stage of the cell cycle?

Answer 6

S (Synthesis) Phase

Question 7

Experiement which proved that DNA is replicated semi-conservatively

Answer 7

Messelson & Stahl Experiment

Question 8

Meaning of “semi-conservative” replication

Answer 8

For the daughter cell: ½ is from the parental strand then ½ is the newly-formed strand

Question 9

N-bases dominantly present in the ori site

Answer 9

adenine & thymine

Question 10

Why is the ori site rich i A & T?

Answer 10

easily broken as it has only 2 bonds

Question 11

During PCR, what is the direction of travel of the DNA?

Answer 11

Cathode (-) to Anode (+)

Question 12

Function of DNA Helicase

Answer 12

Unwinds the double stranded DNA by breaking the H+ bonds between the bases

Question 13

Specific SNA Helicase in E. coli

Answer 13

DNA B Protein

Question 14

-relieves tension when the double strand is unwound

Answer 14

DNA Gyrase

Question 15

• keep the strands from premature annealing through specific binding

Answer 15

Single-stranded binding proteins

Question 16

• synthesizes RNA primers needed to begin the synthesis of daughter strands

Answer 16

Primase

Question 17

Function of DNA Polymerase III?

Answer 17

synthesizing a new daughter strand using one of the parental strands as a template

Question 18

Direction of DNA Synthesis

Answer 18

5’ - 3’

Question 19

T/F: DNA Polymerase III can begin synthesis

Answer 19

False, RNA Primers are needed to begin he synthesis; DNA Polymease III can only add to the existing strand

Question 20

• proofread the chain for mistakes

Answer 20

DNA Polymerases I & III

Question 21

Function of DNA Polymerase I ?

Answer 21

removes primers, closes gaps and repair mismatches

Question 22

Function of DNA Ligase?

Answer 22

binds the nicks in DNA during synthesis & repair

Question 23

Part of the genome (containing the ori) that is replicated as a unit

Answer 23

Replicon

Question 24

Explain: Rolling Circle Mechanism

Answer 24

• replication of one strand that rolls out of the circular DNA
• rapid and continuous DNA Synthesis from a single initiation event

Question 25

Rate of Error in DNA Replication

Answer 25

1 base in every 10^-9 – 10^-10