DNA-RNA-Protein Synthesis
Background
Genes are functional units of DNA. They express themselves by the protein they dictate. DNA is found
in the nucleus, but proteins are synthesized at the ribosome in the cytoplasm. Thus, a messenger molecule is
needed to carry the DNA code. This messenger molecule is called messenger RNA (mRNA). It is rich in
ribose sugar, is formed in the nucleus and tests mildly acidic. Therefore, it was named ribonucleic acid.
The purpose of this lab activity is to review the molecular make-up of DNA as it related to RNA and
protein synthesis. Replication of DNA, transcription and translation of RNA are modeled as well.
Question: Can we model protein synthesis (DNA makes RNA makes proteins) using colored plastic pieces?
Hypothesis: If we use different colors and different shapes to represent molecules and bonds, then we can
model protein synthesis using plastic pieces.
Pre-Lab Questions:
1. Compare and contrast DNA and RNA using a Venn diagram or chart.
2. What is produced during transcription? What is produced during translation?
3. Where does transcription and translation take place?
4. What is the relationship between the codon and anticodon?
Materials
Cytosine – Blue
Thymine – Green
Adenine – Orange/Tan
Guanine – Yellow
Uracil – Purple
Phosphate group – White
Peptide Bond – Grey
Deoxyribose – Black
Pentagon
Hydrogen Bond – White
Rod
Ribose – Purple Pentagon
Procedure
1. On your desk, determine an area that will be the nucleus and the cytoplasm, because
these steps must take place in the appropriate place.
2. Make a DNA molecule that is 9 rungs long. (What color sugar should you use?) You
determine the base pairing. Take a picture of this or draw a picture of your model in your
data section. Title the picture, and label the parts.
3. Now unzip the DNA molecule. Choose one half to use for transcription (you will not nee
the other half anymore). Use this single stranded DNA as a template for your mRNA.
4. Transcription: Make the mRNA and place it parallel to the DNA strand. Remember the
two strands are complimentary and the changes in base pair rules for DNA and RNA.
5. Take a picture or draw a picture of this (title and label all parts, including which strand is
DNA and which is RNA. Put this picture in your data section.
6. The mRNA is now ready to leave the nucleus and go to the ribosome. Unzip the mRNA
from the DNA and move it outside the nucleus and go to the ribosome.
7. Translation: The code for the protein only works in units of three called codons. It is the
job of the tRNA to put the amino acids according to the mRNA codon. Using the mRNA
as a template, attach the appropriate nitrogen base to the tRNA (long purple plastic
piece). The sequence on the tRNA is called the anticodon.
8. The tRNA brings amino acids to the ribosome to make protein. Attached to the tRNA are
the amino acids (long black plastic piece). Attach the correct amino acid to the tRNA.
9. Attach the amino acids with peptide bonds (grey tubes)
10. Take a picture or draw a picture of this labeling all parts (or you may take a picture using
photobooth and label on a Pages/Word document). Put this picture in your data section.
11. Disconnect the tRNA from the amino acid chain. Now you have your free moving amino
acid chain that will form a protein.
12. YOU DID IT….YOU MADE A PROTEIN!!
Conclusion: Write a proper conclusion for this lab. Remember to restate the hypothesis,
accept/reject the hypothesis using evidence from your data, and include 1 SOPE referring to the
design (not procedural error) of the lab.
Post lab Questions
1. Why does DNA stay in the nucleus?
2. Convert the following DNA sequence to amino acids: CTAGCCTATAACTAG
3. Describe a possible consequence to a person whose cells made an error in transcription or
translation.