Building A Protein
This hands-on activity is an assessment of the students understanding of peptide and disulfide bonds formed during protein synthesis, and the structure of an amino acid (R-group plus the common structure that all amino acids share). Students will demonstrate the process of dehydration synthesis by combining amino acids. They will synthesize one molecule of the protein ADH (antidiuretic hormone) by reading the mRNA sequence, cutting out the -OH on the carboxyl group on amino acid one, and the -H on the amino group of amino acid two. These two pieces (-OH and -H) will combine to form a water molecule. The students will connect the two amino acids by taping a peptide bond label between the carbon of the carboxyl and the nitrogen of the amino group on amino acid. This process is continued until the stop codon on the mRNA is read. If the synthesis is done correctly, the student will produce eight peptide bonds creating one chain, and eight molecules of water. If this activity is used for biology, the tRNA, and rRNA molecules can be added to the process.
- Describe the basic structure of amino acids and the formation of polypeptides.
- The interaction of amino acid side chains determine the shape and structure of the protein.
- Translation converts mRNA into a protein using amino acids found in the cytoplasm.
- -Amino acid
- -Carboxyl group
- -Protein synthesis
- -Start codon
- -Stop codon
Context for Use
Resource Type: Activities:Classroom Activity:Short Activity:Demonstration, Activities:Classroom Activity
Grade Level: High School (9-12)
Description and Teaching Materials
Amino Acid Template worksheet (one per student)
mRNA Seq Template
1 Scissor, and 1 roll of tape.
(Biology may add tRNA
One codon translation table or codon translation wheel.
- Assemble the strand of mRNA.
- Cut along the solid lines and tape the three strips of paper together. The second strip that begins with "glu" should be taped to strip number one that ends in "phe". Then tape strip number three that begins with "gly" to strip number two that ends with "arg". You should have one strip of paper with eleven mRNA codons.
- Assemble the amino acids.
- Cut along the solid lines on the Specific Amino Acid worksheet. You will have nine amino acid cards. Then cut out the nine R-groups. Tape one amino acid to one r-group card to create nine specific amino acids.
- Cut out the nine bonds and the eight process labels.
- Using your translation table read two codons following the start codon.
- Find the amino acid cards that match these codons.
- Perform dehydration synthesis to link the two amino acids together.
- Cut out the -OH on the carboxyl group on the first amino acid.
- Cut out the -H on the amino acid on the second amino acid.
- Combine these two piece (-OH and -H ) to form a water molecule.
- Tape a peptide bond label between the carbon of the first amino acid and the nitrogen of the second amino acid.
- Lay the dehydration synthesis label below the peptide bond, and above the water molecule.
- Read and translate the next mRNA codon.
- Perform dehydration synthesis on the last amino acid of your polypeptide chain, and the new amino acid until you read the stop codon.
- Now tape the disulfide bond between the two cystine amino acids.
This can be done verbally or written.
- Have the students describe dehydration synthesis process including the words dehydration synthesis, and peptide bond.
- Explain why there is only one disulfide bond in this chain, and what happens to the protein when the disulfide bond occurs.
Teaching Notes and Tips
- MN 9-12.IV.B.4.1
- Ionic Bonds
- MN 9-12.VI.D.6.1
- Identify synthesis reaction
- MN 9-12.IV.D.1.2
- Relationships DNA, Genes, Chromosome.