Download Table of nitrogen base

©Thomas and Karen Booker
Alien Protein Synthesis
Pre-Lab Reading
Genes are the units that determine inherited characteristics, like hair color and blood type. Genes are composed of
DNA. The DNA code is based on a triplet of nitrogen bases. The triplet code codes for a specific amino acid. Amino
acids combine to form proteins.
In a process known as transcription (takes place in the nucleus) messenger RNA (mRNA) reads and copies the
DNA. mRNA then takes this message out of the nucleus into the cytoplasm to the ribosome (rRNA), the site of protein
synthesis in a process known as translation. It is at the ribosome that the third form of RNA arrives, transfer RNA
(tRNA). Transfer RNA carries a specific amino acid for a specific codon on the mRNA. The tRNA binds to the mRNA
by the anti-codon. This continues until a protein has been manufactured.
In this activity you have collected a sample of alien DNA from a distant planet. This species has 8 genes that you
have designated: 1, 2, 3, 4, 5, 6, 7, 8. Transcribe the DNA into mRNA, then find the anti-codon and the corresponding
amino acid. The series of amino acids will determine the protein (trait).
Problem: How are an organisms’ traits determined? How do the genes ultimately result in a characteristic?
Procedure:
1. To determine the trait for Gene #1 of your alien, write down the DNA sequence from the overhead.
2. Use the Table of nitrogen base pairings to determine the mRNA for Gene #1 of your alien.
3. Use the Table of nitrogen base pairings to determine the tRNA for Gene #1 of your alien.
4. To determine the amino acid sequence, match the tRNA anticodon with the amino acid coded for it, based on the
tRNAs below.
5. The amino acids will combine to form a protein (trait).
6. Repeat steps 1 - 5 for each gene, then draw your alien!
Table of nitrogen base-pairings
DNA  DNA
DNA  mRNA
mRNA  tRNA
TA
TA
U* A
AT
A  U*
A  U*
GC
GC
GC
CG
CG
CG
Phe
Leu
Ile
Start
Val
Ser
Pro
Thr
Ala
Try
Stop
His
Gln
Asn
Lys
Asp
Glu
Cys
Arg
Trp
AAA GAG UAA UAC CAC AGU GGG UGA CGG AUA AUC GUG GUU UUA UUU CUA CUC ACA GCC ACC
Amino Acids
Start-Ser-His-Asn-Asp-Arg-Pro-Stop
Start-Try-Ala-Val-Leu-Gln-Glu-Stop
Start-Arg-Arg-His-Ser-Stop
Start-Phe-Leu-Val-Pro-Stop
Start-Cys-Asp-Asn-His-Try-Thr-Ser-Stop
Start-Ile-Val-Pro-Asn-His-His-Asp-Stop
Start-Val-Val-Stop
Start-Arg-Arg-Stop
Start-Phe-Ile-Pro-Gln-Asp-Cys-Stop
Start-Phe-Trp-Ile-Pro-Gln-Asp-Stop
Start-Try-His-Stop
Start-Pro-Ile-Stop
Start-Try-Ala-Gln-Ser-Lys-Ile-Cys-Stop
Start-Phe-Arg-Ile-Cys-Val-Glu-Ser-Stop
Start-Gln-Asn-Lys-Stop
Start-Thr-Ala-Try-Stop
Proteins (Traits)
green skin
blue hair
big, pointy teeth
long, quick tongue
3 arms
no arms
9 legs
snakelike body
horns
antennae
3 eyes
9 eyes
sharp claws
suction cups on fingers
wings
scaly plates on back
Amino
Acid
anticodon
tRNA
©Thomas and Karen Booker
Name
Period
Data Tables
Alien #:
Gene # 1
Gene # 2
DNA
mRNA
tRNA
DNA
mRNA
tRNA
Amino
Acids
Protein
(trait)
Amino
Acids
Protein
(trait)
Gene # 3
Gene # 4
DNA
mRNA
tRNA
DNA
mRNA
tRNA
Amino
Acids
Protein
(trait)
Amino
Acids
Protein
(trait)
Gene # 5
Gene # 6
DNA
mRNA
tRNA
DNA
mRNA
tRNA
Amino
Acids
Protein
(trait)
Amino
Acids
Protein
(trait)
Gene # 7
Gene # 8
DNA
mRNA
tRNA
DNA
mRNA
tRNA
Amino
Acids
Protein
(trait)
Amino
Acids
Protein
(trait)
Sketch Your Alien!
Analysis & Conclusions
 Briefly describe the steps in Protein Synthesis.
 Describe all 3 forms of RNA and discuss their functions.
 Describe how you could find the DNA if you knew the amino acid sequence. Give an example to illustrate
your point.
 Could a mutation in the DNA affect the way an organism looks? Give an example to illustrate your point.
©Thomas and Karen Booker
Alien Name:
©Thomas and Karen Booker
Recovered Alien DNA Sequences
Species 4672-A
Gene 1: TAC-AGT-GTG-TTA-CTA-GCC-GGG-ATC
Gene 2: TAC-AAA-GAG-CAC-GGG-ATC
Gene 3: TAC-ACA-CTA-TTA-GTG-ATA-TGA-AGT-ATC
Gene 4: TAC-GCC-GCC-ATC
Gene 5: TAC-AAA-TAA-GGG-GTT-CTA-ACA-ATC
Gene 6: TAC-ATA-GTG-ATC
Gene 7: TAC-AAA-GCC-TAA-ACA-CAC-CTC-AGT-ATC
Gene 8: TAC-TGA-CGG-ATA-ATC
Species 4672-B
Gene 1: TAC-ATA-CGG-CAC-GAG-GTT-CTC-ATC
Gene 2: TAC-GCC-GCC-GTG-AGT-ATC
Gene 3: TAC-TAA-CAC-GGG-TTA-GTG-GTG-CTA-ATC
Gene 4: TAC-CAC-CAC-ATC
Gene 5: TAC-AAA-ACC-TAA-GGG-GTT-CTA-ATC
Gene 6: TAC-GGG-TAA-ATC
Gene 7: TAC-ATA-CGG-GTT-AGT-TTT-TAA-ACA-ATC
Gene 8: TAC-GTT-TTA-TTT-ATC