Alien Encounters!
Background: In the year 2050, an incredible archeological
discovery was made in the middle of a remote area of South
America. It was an area where a large meteor had struck the
Earth. A pile of alien bones were found completely mixed up together. The
scientists were able to recover small fragments of DNA which they brought back
to their labs. After much work, they determined that the DNA fragments
represented 9 genes.
Purpose: In this activity, you will determine the traits of these aliens by
analyzing their DNA and determining the amino acid sequences of each the
resulting 9 genes. Each DNA fragment (gene) is associated with a particular
protein and a specific alien characteristic (trait).
Procedure:
1. Put the DNA sequence for each gene in the proper location on your data
sheet.
2. Transcribe the DNA for each gene into mRNA. Record those sequences.
3. Translate the mRNA into amino acids using the provided mRNA Codon Chart.
Record the amino acid sequence for each gene.
4. Use the “Alien Genes” chart to determine the traits that are associated with
each of your amino acids sequences and write those traits on the charts.
5. Using a blank piece of paper, sketch and color your alien, making sure to
include all relevant (known) traits.
Be sure to include your alien’s number at the top of your drawing and data
sheet. Place your name on your drawing.
6. Answer the following 6 questions after you draw your alien picture:
Questions:
1. Did you find any “identical” aliens in your group (your class)? Why?
2. Summarize the 4 steps (from start to finish) you used to identify each trait
of your alien.
3.
How does a single change in a nitrogen base result in a different protein?
4. If you knew a particular amino acid sequence, could you figure out the DNA
for that sequence? Explain how: (you should work backwards)
5. What is the difference between transcription and translation? (location and
end result)
6. What is the role/job and location of each of the nucleic acids involved in
protein synthesis? 4pts
DNAmRNArRNAtRNA-
DATA Tables for Alien Gene Analysis:
Alien Number _______
NAME_____________________
Is your alien hairless or hairy?
GENE A
DNA
mRNA
Amino Acids
Trait
Is your alien fat or skinny?
GENE B
DNA
mRNA
Amino Acids
Trait
Does your alien have 4 or 8 legs?
GENE C
DNA
mRNA
Amino Acids
Trait
What size nose does your alien have?
GENE D
DNA
mRNA
Amino Acids
Trait
Does your alien have antennae?
GENE E
DNA
mRNA
Amino Acids
Trait
What color skin does your alien have?
GENE F
DNA
mRNA
Amino Acids
Trait
How many fingers does your alien have?
Does your alien have a tail?
GENE
G
GENE
H
DNA
DNA
mRNA
mRNA
Amino Acids
Amino Acids
Trait
Trait
Does your alien have 4 eyes or 8 eyes?
GENE I
DNA
mRNA
Amino Acids
Trait
ALIEN GENES
This table shows the amino acid sequences for the various alien genes and
traits.
Gene
Letter
A
B
C
D
E
F
G
H
I
Amino Acid Sequence
Val-pro-ileu
Tryp-pro-ileu
Tryp-val-val
Ileu-ileu-ser
Ser-ala
Ser-ser
Pro-ser-phe-gly
Gln-ser-phe-gly
Lys-phe
Lys-leu
Pro-ala-ala
Pro-ala-asp
Pro-ala-val
Pro-ala-pro
Gln-gln-asp
Gln-gln-lys
Gly-gly-ileu
ala-gly-ileu
Ileu-asp-ala
Ser-asp-ala
Resulting Characteristic
Hairless
Hairy
fat
skinny
4 legs
8 legs
Long nose
Short nose
No antennae
4 antennae
Blue skin
Red skin
Yellow skin
Green skin
10 fingers
12 fingers
tail
No tail
4 eyes
8 eyes
mRNA CODON CHART
After you have decoded all of your DNA bases into the RNA bases you are ready
to use the codon chart below:
How you determine your amino acids are by these steps:
Step 1: Decode the DNA sequence. For example; If your DNA sequence is TAC, then
when you decode it, it will translate into the mRNA, AUG.
Step 2: Use your new code, the mRNA, in this case it is AUG, to read the chart. How
you begin to read the chart is you look at the left hand column in the row of "A" since
that is your first letter in the code. Then look at the top row of the chart and find the
column "U" since that is your second letter in the RNA code. Lastly, move your eyes
across to the "G" row on the right side of the chart. Where all three letters meet is
your amino acid! Which in this case is "MET