Integrated Science II
Chapter 8 Lab
Name ___________________________________
Period ______
/20
DNA and Protein Synthesis Simulation
Proteins like skin and hair pigments, structural proteins such as keratin
and collagen, enzymes, and numerous others control all cell activities and
ultimately our physical traits. The DNA that we inherit from our parents
and eventually pass on to our children contains the information for making
these proteins. This genetic code is first transcribed into an mRNA molecule which is then translated by a ribosome in
the cytoplasm to make the protein. Changes in DNA or mutations result in changes in a protein which can be harmful.
Objective:
A. Simulate the processes of transcription and translation.
B. Introduce the concept of genetic mutations and understand how they may harmful.
Procedure:
Base Pairing Rule
A. Replication
A–T
C–G
1. Complete the base pair sequences for each strand of DNA
on the blue worksheet “DNA Strands”.
2. Now that you have completed your DNA, cut out your two DNA strands.
_____________
Teacher Sign-off
a) What is the name of the process by which DNA can copy itself? ______________________________
b) Why is DNA replication so important for life? ______________________________________________
B. Transcription
1. Cut each strand in half along the dotted line. This represents the “unzipping” that DNA must go through in
order to build protein. Save the DNA strands that you constructed (right-hand half).
2. On the pink worksheet “RNA Strands”, there are two chains labeled RNA 1 and RNA 2. It is here that you
are going to construct the RNA 1 that corresponds to the DNA 1 and RNA 2 from DNA 2. Place your half
of DNA 1 over RNA 1. Place your half of DNA 2 over RNA 2.
DNA
RNA
3. In order to construct RNA from DNA, it is important to remember
C
G
the matching sequence shown in the table on the right.
G
C
T
A
*Note the change that makes RNA different from DNA.
*A
U*
RNA substitutes a “U” (Uracil) for the “T” (Thymine) in DNA.
4. Write the appropriate matching bases for RNA 1 and
_____________ Teacher Sign-off
RNA 2 in the blanks of the RNA strips.
a) Name the process where DNA copies its genetic information to RNA? __________________________
b) What are the triplets of bases on messenger RNA called? ____________________________________
C. Translation
1. At the bottom of this same pink worksheet, cut out the Ribosome: “Protein Factory”.
2. Move your ribosome along RNA strand 1 from left to right with the window facing up. This will allow you to
read one codon at a time. Repeat the process for RNA 2.
a) How many RNA bases make up one codon? ________
b) List the codons for RNA 1. __________ __________ __________ __________ __________
C
h
a
r
C t
o
d
e
C
h
A
G
U
C
Lysine
Lysine
Asparagine
Asparagine
Glutamic Acid
Glutamic Acid
Aspartic Acid
Aspartic Acid
“Stop” codon
“Stop” codon
Tyrosine
Tyrosine
Glutamine
Glutamine
Histidine
Histidine
A
Arginine
Arginine
Serine
Serine
Glycine
Glycine
Glycine
Glycine
“Stop” codon
Tryptophan
Cysteine
Cysteine
Arginine
Arginine
Arginine
Arginine
Isoleucine
Methionine/Start
Isoleucine
Isoleucine
Valine
Valine
Valine
Valine
Leucine
Leucine
Phenylalanine
Phenylalanine
Leucine
Leucine
Leucine
Leucine
Threonine
Threonine
Threonine
Threonine
Alanine
Alanine
Alanine
Alanine
Serine
Serine
Serine
Serine
Proline
Proline
Proline
Proline
G
U
C
Second Letter in Codon
A
G
U
C
A
G
U
C
A
G
U
C
A
G
U
C
Third Letter in Codon
G
e
n
e
t
i
c
First Letter in Codon
c) List the codons for RNA 2. __________ __________ __________ __________ __________
3. Use the Genetic Code Chart on the previous page to determine which amino acid is coded for each codon. Once
you have determined which amino acid corresponds to the first codon, write the name of the amino acid in the first
blank space below. Continue for each codon. Repeat this process to determine the amino acids from RNA 2.
Protein 1 (amino acid sequence) from RNA 1
Protein 2 (amino acid sequence) from RNA 2
a) What are the building blocks of proteins? _______________________________________________________
b) How many different amino acids are there? _____________________________________________________
c) What is the purpose of the start codon? ________________________________________________________
d) What is the purpose of the stop codon? ________________________________________________________
e) What is the site of protein synthesis in the cell?__________________________________________________
4. Return your scissors and place any scrap paper in the recycling bins.
Analysis: [Refer to class handout for information about sickle-cell anemia and hemoglobin]
A. What is the difference between proteins 1 and 2? ____________________________________________________
B. Changes or mistakes in DNA are called ____________________________________________.
C. Protein 1 is from normal hemoglobin. Protein 2 is from hemoglobin of a person who has sickle-cell anemia.
1. What is the role of hemoglobin?________________________________________________________________
2. What are the symptoms of this disease? _________________________________________________________
D. DNA sequence 1 is for normal hemoglobin. DNA sequence 2 is for hemoglobin in people with sickle-cell
anemia. How many changes in the DNA base code are involved in this mutation?___________________________
E. How can a single change in a DNA nucleotide alter the formation of the translated protein? ___________________
_____________________________________________________________________________________________
_____________________________________________________________________________________________
F. Refer to the Genetic Code Chart. How many codons code for the amino acid leucine?________________________
G. Would a mutation where the codon ‘CUA’ was changed to ‘CUG’ cause any harmful change? Explain ___________
_____________________________________________________________________________________________
Conclusion:
A. Purpose: ______________________________________________________________________________________
_______________________________________________________________________________________________
B. Summary of Results: ____________________________________________________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________
C. Interpretation and Analysis: ______________________________________________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________
D. Conclusion:____________________________________________________________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________