Download Practice using the RNA codon * amino acid Codon Chart*

Protein synthesis: DNA to RNA  protein
Name _____________________________________________________________ Date: ________________ Period: __________
INTRODUCTION: Protein synthesis is the process used by the body to make proteins. The first step of
protein synthesis is called Transcription. It occurs in the nucleus. During transcription, mRNA
transcribes (copies) DNA. DNA is “unzipped” and the mRNA strand copies a strand of DNA (base pairing
exception- RNA uses Uracil instead of Thymine.) Once it does this, mRNA leaves the nucleus and goes
into the cytoplasm. mRNA will then attach itself to a ribosome. The strand of mRNA is then read in order
to make protein. They are read 3 bases at a time. These bases are called codons. tRNA is the fetching
puppy. It brings the amino acids to the ribosome to help make the protein. The 3 bases on tRNA are
called anti-codons. Remember, amino acids are the building blocks for protein. On the mRNA strand,
there are start and stop codons. Your body knows where to start and stop making certain proteins. Just
like when we read a sentence, we know when to start reading by the capitalized word and when to stop
by the period. (Need more information?? See pg. 525-530 in BSCS text)
A protein is a string of amino acids bonded together.
The order of amino acids is determined by the sequence of base codons in a RNA molecule.
Example RNA base sequence: G A C G A U G U A G C A U C G A C C A U U G
Every 3 bases (a codon) in the RNA codes for 1 amino acid.
Example: C C A codes for proline
Can you use the chart below to figure out how C C A codes for the amino acid proline?
1. Use the codon chart to write the amino acid that corresponds to each codon.
CGG ___________________________
CUG ___________________________
AGC __________________________
CAG ___________________________
UAA __________________________
CGA ___________________________
AUG __________________________
UUG ___________________________
2. Write a codon that corresponds to each amino acid.
There may be more than one.
serine ___________________
leucine ___________________
aspartate ___________________
threonine ___________________
glycine ___________________
arginine ___________________
histidine ___________________
cysteine ___________________
3. Can there be more than one amino acid for each codon?
Yes
No
4. Can there be more than one codon for each amino acid?
Yes
No
5. Make a protein: Break the following RNA base sequence into codons (draw a line after every 3 bases).
Use the Codon Chart to determine the sequence of amino acids coded for by this RNA sequence.
Write out the order of amino acids.
RNA base sequence:
AUGCGCCUGACGCUAGGCUAAGCGCGUAACGCAGUCGCA
Amino acid sequence:
6. You just made a protein! In the cell, which organelle makes protein? _____________________________________
7. Now, let’s start from the beginning…. With a DNA strand.
1. DNA  CCT CTT TAC ACA CGG AGG GTA CGC TAT TCT ATG ATT ACA CGG TTG CGA TCC ATA ATC
mRNA 
protein 
2. DNA  AGA ACA TAA TAC CTC TTA ACA CTC TAA AGA CCA GCA CTC CGA TGA ACT GGA GCA
mRNA 
protein 