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Name___________________________ Lab #____________ Role: _________________
Activity 1. Protein Synthesis
In this activity, you will model the steps of protein synthesis. Before beginning,
your group should have:
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20 amino acid links each labeled as a different amino acid
30 pop beads of each color
30 connector pieces
mRNA Codons for Amino Acids chart
colored pencils
Key:
Adenine—red pop bead
Thymine—yellow pop bead
Guanine—blue pop bead
Cytosine—purple pop bead
Uracil—orange pop bead
Hydrogen bonds—clear connectors
1. Working in groups of three, build a DNA strand with pop beads
using the key provided. (Note: This does not represent an actual
DNA sequence, the DNA sequence is used for demonstration
purposes only). Build the DNA strand using the order of
nucleotides in the diagram below. Your DNA strand will be 25
bases long. Color the diagram below according to the key, using colored pencils.
NOTE: Replication is not a part of protein synthesis but will be demonstrated here for practice.
2. Practice replication by copying the above DNA strand to form a complementary DNA strand. Use the clear connectors
to form “bonds” between complementary nucleotide bases by inserting the connector into the bottom of the original
DNA nucleotide base and the top of the replicated DNA nucleotide base. Fill in the replicated DNA strand below with
each nucleotide and color using colored pencils according to the key. When you have completed your strand, you will
have a DNA double strand. Twist the two strands to create a double helix.
Replicated DNA Strand
3. Once your replicated strand has been checked by your teacher, separate the two strands and set aside the original
strand. Transcribe the replicated DNA strand into an mRNA strand. Use the same process for connecting the DNA and
mRNA strands as was followed in Step 2. Record the transcribed mRNA strand below and color it accordingly.
mRNA
4. Using the transcribed mRNA strand, begin the process of translation. You will need the mRNA Codons for Amino Acids
chart and the amino acid links that you labeled before you began the lab. Set the links off to the side. Begin translation
by locating the start codon on the mRNA strand.
5. You will now use the pop beads to create a tRNA molecule that is complementary to the start codon. Connect the three
complementary beads to one another.
6. Once the complementary tRNA anticodon is in place, determine the appropriate amino acid by using the chart.
Retrieve the correct amino acid link and bring both the tRNA and amino acid back to the mRNA strand. Attach the tRNA
and lay the amino acid above the tRNA strand. This amino acid link will be the beginning of your protein chain.
Name___________________________ Lab #____________ Role: _________________
7. After the first amino acid is in place, locate the next codon.
Assemble the complementary tRNA anticodon and repeat
Step 6.
8. After the second amino acid link is brought to the mRNA
strand, begin forming the protein chain by separating the
amino acids from the tRNA and linking them together, as
shown.
9.
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Continue building the protein chain by locating amino acids and making tRNA anticodons and bringing the anticodons
and amino acids to the mRNA to connect the amino acids together to form a chain. Your protein chain will be complete
when you reach the stop codon. There is no amino acid associated with the stop codon.
10. When your chain is complete, record the amino acids in order from the start codon to the stop codon on the diagram
below.
11. Have your teacher check your protein chain. Then, disassemble all strands and amino acid links except for the original
DNA strand. Save this strand for Activity 2.
Activity 2. Genetic Mutation
You and your group will design an experiment to observe the effects that changes in DNA have on proteins. You will need:
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30 pop beads of each color
30 connector pieces
20 amino acid links w/ labels
3 amino acid links w/ blank labels
1.
3.
For this activity, you will use the original DNA strand from Activity 1. The strand should look like the diagram below:
2. With your group, brainstorm ways that this DNA strand could be altered. List some examples here:
Choose one of the changes that you listed in Step 2 to experiment with. Explain below how you will alter the DNA strand &
make these changes on your DNA model. If you need additional pop beads, I will supply them for you. Record the altered
DNA strand on the following diagram. Note: Beads have been added to the diagram. If you remove beads, simply mark
them off of your strand with an X.
Altered DNA Strand
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4.
Record a prediction of how you expect to the change in DNA will affect the protein at the end of protein synthesis.
Prediction:
5.
Complete the steps of protein synthesis from Activity 1 with the altered DNA strand from Step 3. Begin with
transcribing the altered DNA into mRNA. Record the mRNA strand below. (Note: Cross off any beads you do not use
with an X.)
6.
After completing the steps of translation from Activity 1, label the amino acids (if any exist) from the completed protein
chain on the diagram below. (Note: Cross of any links you don’t use with an X.)
7.
Take note of the changes that took place in protein synthesis due to the altering of the DNA strand. Describe the
changes that occurred in the protein.
8.
Go the board and write out your original chain, type of mutation, and the resulting protein chain. We will compare the
class results at the end. Put all of your supplies away neatly and push in your stools. Go back to your desks and wait
patiently for everyone to finish.