From Gene to Protein: DNA Transcription and Translation
Carlin Hsueh (2011)
Grade Level: 7th grade
Classroom size: ~36 students
Time required: 50 min
Supplies:
1. Printed double-stranded DNA “strands” containing two gene sequences (separated by a
marked line in the nucleotide sequence)
2. Complimentary mRNA bases (G, U, A , C)
3. Amino Acids (#1-6) with corresponding 3-base sequence on back (codon)
4. Proteins S(ickle) & N(ormal), with amino acid sequence on back
5. Power point presentation
6. Prizes (candy)
Lesson Abstract:
In our bodies, the instructions for making a protein are provided by a gene, which is a specific
segment of a DNA molecule, and proteins influence our characteristics. However, when these
instructions are misread is can cause drastic changes in a person’s characteristics and health.
For example, most of us have a protein enzyme that can create melanin, the main pigment that
gives color to our skin and hair. In contrast, albino people make a defective version of this
protein enzyme, so they are unable to make melanin and they have very pale skin and hair.
So where is the problem? DNA and proteins have different languages. It’s like trying to build a
shelf but the instruction manual is in Russian. Luckily, there are steps our cells take to translate
the instructions in our DNA so that they can build proteins.
1. The instructions in the gene in the DNA are copied into a messenger RNA (mRNA) molecule.
The sequence of bases in the gene determines the sequence of bases in the mRNA. This step is
called transcription.
2. The instructions in the messenger RNA are used by ribosomes to build the correct amino
acids in the correct sequence to form the protein coded for by that gene. The sequence of
bases in the mRNA determines the sequence of amino acids in the protein. This step is called
translation.
This lesson allows students to act out the transcription and translation process and see how
mutations are possible if a DNA sequence is read wrong. The students are translating and
transcribing a normal gene sequence and a gene sequence correlated to sickle cell anemia.
Lesson Outline:
1. Power point introduction to DNA transcription and translation
2. Split class up into 4 teams of 8 students with roles consisting of (1)DNA, (1) mRNA, (2)
Cytoplasm 1, (1) Ribosome, (2) Cytoplasm 2, and (1) Protein. Students can decide their
own roles, which are:
 DNA – you are in charge of splitting the DNA open so that the messenger RNA can
copy the genes.
 Messenger RNA (mRNA) – you are in charge of copying the genes on DNA one base
at a time. Each gene will end at a line so you’ll know when to stop copying gene 1
and when gene 2 begins.
 Cytoplasm 1 (nucleus) – Two of you are in charge of supplying the bases to the
mRNA so that it can copy the genes in the DNA
 Ribosome – you are in charge of taking the mRNA and building the amino acids from
the mRNA’s sequence.
 Cytoplasm 2 – Two of you are in charge of supplying the amino acids to the
ribosome so that it can build a protein from the mRNA sequence.
 Protein – you are in charge of taking the amino acid chain from the ribosome and
finding what protein it is producing (S or N)
 (Optional) Doctor – One doctor for the entire classroom who will wait outside the
activity room and waits for the proteins to be delivered by the teams. The doctor
acts as someone who keeps track of which teams finish first but also as the person
who displays the final results of each team (ie, what proteins that team produced)
3. The activity will run like a relay race, where the DNA will split open to reveal the base.
The mRNA will need to match the complimentary base (remember, U for T) base-bybase to replicate how DNA is actually read in the cell. When students hit the dotted line
in the sequence that means they have transcribed the first gene sequence and the
mRNA can pass this first transcription to the ribosome. The following sequence are for
gene sequence #2 (remember, they are producing two proteins) and will also be given
to the ribosome after transcription.
The cytoplasm will help grab the complimentary bases as the mRNA calls them out.
Once the gene strand is transcribed it will move to the ribosome where the 3-base
codons are matched with an amino acid #1-6 that will have 3-base sequences printed on
the back.
These will be strung together in the exact order and then transferred to the protein who
will need to match the amino acid chain sequence to a matching protein with a number
sequence (1-6) also printed on the back.
Each DNA strand will produce two proteins, either a combination of Protein SS, Protein
SN, Protein SN, or Protein NN. The proteins will then run their choices to the doctor
who will display their “diagnosis” on the board for everyone to see.
If the DNA is misread, then the sequences are off and there will be no amino acid to
match the sequence with or proteins to choose from. Thus, the team will have to return
the mRNA to the DNA and find the “mutated” section. This is called DNA repair, and
then whole process repeats with the repaired mRNA.
4. Wrap up: Discussion on activity and results. This is when the teacher will reveal that
Protein S stands for Sickle Cell Anemia and Protein N stands for Normal Proteins. The
teacher will also take this time to discuss how easy it was to misread one base and how
that “mutation” can cause havoc further down the process. A simple mutation in the
DNA sequence can cause significant changes in a person’s health, such as developing
sickle cell anemia, a disease that only differs by one base from a healthy protein.
Pre-Lesson preparation:
1. Set up relay stations by placing double stranded dna into boxes so that students must
pull out the DNA to observe each base one-by-one.
2. Complimentary mRNA bases and tape (masking tape works best since it won’t tear the
paper when you have to reset the relay race for another period or for DNA repair)
3. Amino acids #1-6 and masking tape. Add more than the required amount of amino acids
so that the students will have excess amino acids. This prevents them from jumping
ahead and guessing the amino acid sequence instead of reading the entire mRNA
sequence.
4. Proteins S and N. Again, add more than the required amount of Proteins S and N so that
students cannot predict the proteins before seeing the amino acid sequence.
Quick Tips:
1. Do a practice run with the first 6 bases in the DNA sequence so that students get an idea
of how to read the bases and tape together the complimentary mRNA and the amino
acids. The first 6 bases are the same for all the sequences so you can check to make sure
students are reading the bases correctly and putting them in the right order. Reset the
DNA back into the box so the students will start from the beginning again.
2. Reward the first group who submits the correct proteins for that team with a prize.
Candy is always an easy reward.
Attachments:
Power point presentation that includes the handouts and an animation of DNA transcription
and translation. Slides #1-3 are hand outs and slide #4 is the animation.
References:
Lesson adapted from http://serendip.brynmawr.edu/exchange/waldron/gene