DNA Replication Model Activity
BACKGROUND INFORMATION:
A cell’s genetic material (DNA) must be replicated or copied in anticipation of cell division. The new
cells that form after cell divide must be completely alike and have exactly the same amount of DNA to
function normally.
The process of DNA replication has three steps: 1) the DNA molecule unzips; 2) new nucleotides
are added to each side of the original DNA molecule; and 3) enzymes zip up and complete the two DNA
molecules.
PRE-ACTIVITY QUESTIONS:
1. What organic compound grouping does DNA belong to?
2. What is the monomer (basic unit) of the DNA molecule called?
3. What are the three parts of the DNA monomer?
4. What are the four nitrogen bases in DNA and how do they pair with each other?
5. What type of chemical bond holds the two strands of DNA together?
6.
Why is DNA important for living organisms?
7.
What does it mean when it is said that all living organisms have a universal genetic code?
8. Explain what is meant by if there are only 4 nucleotide types in DNA, why are all living things so
different?
9. Where in the cell does DNA replication take place?
10. What happens during DNA replication?
11. Why is it important that an exact copy of the original DNA is made before cell division (EX: if your
body makes new skin cells or new blood cells)?
DNA REPLICATION MODELING ACTIVITY
1. List the order of the nitrogenous bases on the left side of the original DNA molecule (see page 3 of this
handout). Then list the order of the bases found on the right side.
ORIGINAL DNA MOLECULE
LEFT SIDE
_________
_________
_________
_________
_________
RIGHT SIDE
__________
__________
__________
__________
__________
2. Complete the activity steps for modeling DNA REPLICATION found on page 3 on this handout.
3. In the chart below show the results of what happened to the original DNA model when it underwent
replication. List the nitrogenous bases on the lines. How do the strands compare? _______________
NEW DNA MOLECULE #1
OLD STRAND
NEW STRAND
____________
____________
____________
____________
____________
____________
____________
____________
____________
____________
NEW DNA MOLECULE #2
OLD STRAND
NEW STRAND
____________
____________
____________
____________
____________
____________
____________
____________
____________
____________
Name
Class
Date
DNA REPLICATION MODELING
KEY:
T=
1. Fold a flap to the
back of the page
 along this line.
A=
C=
G=
S=
P=
ORIGINAL DNA
STRAND
2. Follow your
teacher’s model
and
fold page in half
on this line.
t
Draw in new DNA
strand here
ORIGINAL DNA
STRAND
3. Fill in the shapes for the original
DNA strands with the letters A, T,
C, G, S, and P.
4. Color in the key and the original
DNA strands according to the key
you set up.
5. To replicate the original DNA, draw
in, label and color complementary
nucleotides for 2 new strands
formed by DNA replication.
6. Compare/contrast the original DNA molecule (old strands) with the 2 new DNA
molecules created by the replication process. How is this unlike making a photocopy of
the original DNA molecule?