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K’NEX DNA Replication and Transcription
Activity
For this activity you will be using K’NEX blocks to build, copy and transcribe
DNA. You should use the glossy manual included with the kit as a reference
for the following activities.
Objectives:
 Construct a DNA molecule with correct base pairing and strand
polarity
 Describe base pairing in DNA and how it is used in replication
 Use a DNA template to construct a mRNA
-DO NOT COMBINE KITS!!!!
-Piece reference sheet: p. 3
Activity 1: Building a Basic DNA Molecule
You will build a molecule of DNA using the procedure outlined on pp 4-5 in
the following way.
1. Assemble nucleotides (24 total)
 Remember to make sure your bases match up (if you build 7
guanines how many cytosines should you build?)
2. Assemble your 12 base pair DNA molecule and display it on the stand as
outlined as on pp. 6+7.
3. Have Mr. Curry inspect your molecule to make sure it is correctly
assembled and initial here:
Extension/Discussion:
1. Why did you assemble nucleotides before assembling you DNA molecule?
2. What was the sequence of your DNA molecule?
3. How many purines does your strand contain? How many pyrimidines?
4. Look at the molecule produced by two other groups. What were their
sequences?
Group 1’s sequence:
Group 2’s sequence:
5. What was the chance that you produced the sequence of nucleotides that
you produced?
6. Is it likely that another group in the class would produce the same
sequence that you did?
7. When the gray connector is snapped together with the light blue clip and
the purple rod what bond is being simulated?
8. Explain what a DNA molecule would look like if purines paired with purines
and pyrimidines paired with pyrimidines.
Activity 2: Replication of a DNA Molecule
You will now replicate your DNA molecule by making a new, complementary
strand to your original strand according to the semiconservative model.
1. Use pp. 10-13 in the glossy manual.
2. Build the appropriate nucleotides that you will need to replicate your
DNA.
 Use the yellow for deoxyribose in the replicating strand
 You know how many and of what type to build your nucleotides, plan
below how many A, T, G, and Cs you will need to build below.
A:
T:
G:
C:
3. Have Mr. Curry inspect your molecule to make sure it is correctly
assembled and initial here:
Extension/Discussion:
1. Compare your original DNA strand to your copies. How are they similar?
How are they different?
2. How does the structure of DNA help make sure copies are exactly the
same as the original strand?
3. What could be the consequence to the cell if DNA failed to replicate
exactly?
Activity 3: Production of mRNA from a DNA Template
1. Use pp. 18-19 in the glossy manual
2. Unzip your DNA molecule making sure to leave all of the connecting
pieces on the side you intend to transcribe.
3. Have Mr. Curry inspect your molecule to make sure it is correctly
assembled and initial here:
Extension/Discussion:
1. Name three major differences between DNA and mRNA.
2. Think about what you did to produce your mRNA molecule. What role
were you taking on in the process?
3. Where, in the cell does transcription occur?
4. Where does the mRNA transcript go after being transcribed?
5. What must happen to the primary mRNA transcript before leaving the
nucleus?
6. List the codons included on your mRNA transcript.
7. The strand that you DID NOT transcribe is called the coding strand.
Why do you think it is called that?
8. Use p. 303 in your text to determine the amino acid sequence that your
mRNA codes for.