Biology - HOT Science Lab

Student
Protein Synthesis: Transcription and Translation
(Adapted from: Protein Synthesis Lab, www.Accessexcellence.org)
NGSSS:
SC.912.L.16.3 Describe the basic process of DNA replication and how it relates to the
transmission and conservation of the genetic information. (AA)
Background Information:
Protein synthesis involves a two-step process. One strand of the DNA double helix is used as a
template by the RNA polymerase to synthesize a messenger RNA (mRNA). This mRNA
migrates from the nucleus to the cytoplasm. Then, in the cytoplasm, the ribosomes bind to the
mRNA at the start codon (AUG). The ribosome moves from codon to codon along the mRNA as
amino acids are added one by one to form a polypeptide (amino acid chain). At one of three
stop codons, the amino acid chain or polypeptide chain will stop forming. The instructions on the
mRNA are very specific and usually only code for one type of protein. If a ―mistake‖ is made,
such as a deletion, inversion, or substitution, the whole protein may or may not change. This
could be either harmful, or beneficial.
Given the DNA code for the hormone insulin, you will determine the correct amino acid
sequence of a molecule. This exercise is divided into three strands of DNA that need to be
coded for their proteins. Each strand represents the beginning, the middle, or the end of the
insulin molecule. Based on the DNA code, the student will determine which segments is the
beginning, middle, or end of the insulin molecule. Once they have determined their segment,
they will group up with the missing two segments and complete the exercise.
Problem Statement: What effect would occur from the change in the exact chemical makeup of
a protein
Vocabulary: transcription, translation, codon, anti-codon, messenger RNA (mRNA), mutations,
substitution, inversion , deletion, duplication, non-disjunction, transfer RNA (tRNA), ribosomes,
polypeptide, amino acid
Materials (per group):
Pencils
DNA strands worksheet
Procedures:
1. Decode the strands of DNA given you. Write out the resulting m-RNA in your chart
given.
2. Divide the m-RNA into its codons by placing a vertical line between them.
3. Using the amino acid chart found below, determine the name of the amino acid
that each codon codes for. In the chart below, write the abbreviation of the amino
acids in their proper order.
4. After examining the polypeptide chains just constructed, determine if it is a
beginning, middle, or an end segment of the pro-insulin molecule. (Hint: Look for a
start code at the beginning, a stop code at the end, or no stop or start code.)
Biology HSL Page 211
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