Download Alien Encounters

Alien Encounters!
Guiding Question: What is the relationship between DNA, mRNA, proteins, and actual traits?
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 was found completely mixed up together. The explorers who made the
discovery immediately informed the organization known as Scientific Phenomena Over Our
Fabulous Sphere (S. P. O. O. F. S). S. P. O. O. F. S. sent out its best scientists to collect DNA
samples. (Yes, these aliens really did have DNA!) 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 unfortunate recovered aliens by
analyzing their DNA and determining the amino acid sequences of the resulting small protein
fragments. Each fragment is associated with a particular gene and a specific alien characteristic
(trait).
Procedure:
1. Your teacher will give you a unique DNA sequence.
2. Put the DNA sequence for each gene in the proper location on your data sheet (page 3).
3. Transcribe the DNA for each gene into mRNA. Record these sequences on the line that
reads mRNA on your data sheet
4. Translate the mRNA into amino acids using the provided mRNA Codon Chart (top of
page 2) Record the amino acid sequence for each gene at the indicated location on your
data sheet.
5. Use the “Alien Genes” chart (bottom of page 2) to determine the traits that are associated
with each of your amino acids sequences and write those traits on the data sheet in the
indicated location.
6. Complete the Analysis Questions on page 4.
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mRNA CODON CHART
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
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Data Sheet for Alien Gene Analysis
NAME_________________
Alien Number Assigned to you by your teacher _______
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 legs 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 or not?
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?
GENE
G
DNA
mRNA
Amino Acids
Trait
Does your alien have a tail?
GENE
H
DNA
mRNA
Amino Acids
Trait
Does your alien have 4 eyes or 8 eyes?
GENE
I
DNA
mRNA
Amino Acids
Trait
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ANALYSIS QUESTIONS
1. Draw a picture of your alien, making sure to include all relevant (known) traits. You may do
this in a drawing program on your computer, or do it on a blank sheet of paper by hand. If
done electronically, try to copy/paste it here. If you draw it by hand you may scan it or take a
picture with a phone and email or text it to me. I am fine with receiving your picture in any
form that you can send it! Be sure to include your alien’s genus and species at the top of your
drawing and data sheet.
2. Give the tRNA sequences for Gene D.
3. How does a single change in a nitrogen base alter the formation of a resulting protein?
4. If you knew a particular amino acid sequence, could you figure out the DNA for that
sequence? Why or why not?
5. What is the difference between transcription and translation?
6. What are the roles of the DNA, mRNA, and tRNA in protein synthesis?
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