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DNA’s Secret Code
Summary:
Every cell in our body contains DNA. DNA is a set of instructions that tells our cells how to build protein.
Proteins are the building blocks of cells. Just as a long chain of pearls is called a
necklace, proteins are basically long chains of amino acids. Different chains of
amino acids make proteins different from each other. So how do the cells know
which amino acids to make?
A strand of DNA looks like a ladder. The rungs of this ladder are made up of bases.
Each rung is a pair of two bases that are bonded together in the middle. The four
bases used in DNA are Cytosine (C) , Guanine (G) , Adenine (A) , and Thymine (T)
and are paired together in a specific way: Adenine with Thymine, and Guanine
with Cytosine. The order that these base pairs occur in determines the type of
amino acid the cell should make to make the right protein.
A sequence of three bases is called a codon. Codons are like sequences of dots and dashes in a Morse
code. In this activity, you will translate a message into the language that DNA uses, which is the DNA
code. You can also use the DNA code to send secret messages to your friends or family.
Pre-Lab Questions:
What does DNA instruct cells to build?
What is protein?
What is protein made of?
What are the four bases in DNA?
Which bases pair together?
What is the sequence of three base pairs called?
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In this activity we will:
• Translate a message from English to the DNA code
• Understand how DNA genes to build specific proteins
Activity:
1. Write down a secret message to your partner. Keep the message relatively short. (4 words or less)
2. Using the DNA code on the back of this packet, translate the message into DNA code. As you will
notice, all possible English letters and numbers have a specific DNA codon.
Swap with a partner, decode their DNA code. Write it below.
3. When decoding real DNA, it’s a little trickier. Instead of just looking up the codons, you need to
translate the DNA code first and then transcribe it. The codes shown below aren’t decrypted (decoded)
yet. Your first task is to decode the DNA using the knowledge that every A and T always code for each
other and C and G always code for each other. For example, the code ATT GCT GAT would be translated
TAA CGA CTA, which would code for certain letters using the decrypter.
Gene 1) GAG TGT TTC TAC TTA TCT TAG TGC AAC GAG CGA GCC AAC TCT GTC AAC
TGG GGT TAG AAA
Gene 2) CTG GGT TAT TTT TAG AAC GAG CGA GCC AAC TTC TAC TAG GTA TTT TCT
TAG GTC AAC AGC AAC TTG TCT TCA TCA TCT TAC TAG AAC TTG TTT GTC
TGT AAC TAA TTT TCT GTG GTC AAA
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Gene 3) CAG TGA TGT AAC GTA TAC GTA TTT TCA AAC TCA TGT TAG TGC GTA TGA
AAC TAC TGG AAC GAG CGA GCC AAC TCT TAG AAC AGT AAC TGA GGT TAT
TTT TAG AAC TGT GTT GGT TTT TCA GTC AAC ACC AAG AAC GTG TAG GGT
TAG TTA AAC GTA GTG TCT TTA GTC AAC TGG GTG TAC TAT AAC GTA TGA
TGT AAC GAC TTT GTG GTA TGA AAC GTA TAC AAC GTA TGA TGT AAC CAT
GGT TAG AAA