Biology
Unit 4 Molecular Genetics
Topic- DNA Replication
Name: ______________________________________
Date: ______________________ Hour: ___________
Instructions
1.
Go to this website: http://www.wiley.com/college/pratt/0471393878/instructor/animations/dna_replication/index.html and watch/ listen to the animation.
2.
As you work, complete the review questions. Mark the correct answers below.
Review Question 1
1.
Semi-conservative replication means that: a.
DNA is copied by an evolutionary conserved mechanism to ensure that few mutations occur. b.
The newly made DNA double helix consists of two new DNA strands, while the parental DNA retains the two original strands. c.
The two resulting DNA copies each have one strand of parental DNA and one newly constructed strand. d.
The copied DNA is almost identical to the original DNA.
Review Question 2
Match the following enzyme with its function. Write the correct function on the lines below.
A.
Polymerase ________________________
B.
Helicase ________________________
C.
Ligase ________________________
D.
Primase
E.
RNAse HH
________________________
________________________
F.
Sliding clamp ________________________
G.
SSB ________________________
Removes RNA primers
Creates RNA primers
Prevents reannealing
Separates DNA strands
Review Question 3
A replication fork is: links short DNA chains
Creates DNA primers extends DNA chain helps hold polymerase on DNA a.
An area where the DNA separates into two strands and new DNA synthesis occurs b.
A molecular utensil required to stab nucleotides needed for DNA synthesis c.
The point where the cell must decide whether to replicate its DNA d.
A ‘factory’ made of many enzymes that bind DNA for replication.
Review Question 4
The antiparallel nature of double stranded DNA means that a.
The two strands run from 5’ to 3’ in opposite directions b.
The 5 ‘ ends of the two strands are on the opposite ends of the DNA molecule. c.
The two DNA strands twist around each other in a helical pattern. d.
A and B a.
A and C

Review Question 5
The lagging strand: a.
Is synthesized as one continuous strand, making it lag behind the other strand, which is made in many pieces at once. b.
Is synthesized as a series of Okazaki fragments. c.
Is more heavily coated with SSB proteins, slowing down synthesis. d.
Is synthesized more slowly due to the presence of the sliding clamp.
Review Question 6
RNase H aids DNA replication by a.
Removing RNA primers so that they can be reused. b.
Creating RNA primers for DNA polymerase to extend. c.
Degrading RNA bound to a DNA template. d.
Turning RNA into DNA.
Review Question 7 Drag the appropriate component to the DNA strand to model the steps of DNA replication. Write the component name next to each action below.
Action: What separates the DNA Strand?
Action: What coats the single stranded DNA molecule?
Action: What synthesizes RNA primer?
Action: What extends the DNA strand?
Action: What increases processivity?
Action: What removes RNA primer?
Action: What fills in the gap?
Action: What connects short strands of DNA?
Review Question 8
In the factory model of DNA replication: a.
DNA moves through a complex of stationary DNA replicating enzymes. b.
The ‘factory’ of DNA-replicating enzymes moves along the DNA like a train on a railroad track. c.
DNA is the only critical commodity produced by the cell. d.
DNA replication enzymes are compared to a factory because they continuously produce new DNA for the cell.