Transcript Making protein (translation)

Protein Synthesis
Part II:
Translation
• Using the length of messenger RNA to
assemble amino acids into proteins.
• Takes place in a ribosome.
Step 1:
-mRNA is attached to a ribosome
ribosome
Step 2:
-The ribosome “reads” the mRNA three bases at a time.
-These three bases are called the mRNA codon.
ribosome
mRNA “codons”
Step 3:
-The ribosome guides a different type of RNA to each codon.
-This type of RNA is called transfer RNA (tRNA).
valine
mRNA “codons”
Transfer RNA (tRNA)
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Made of RNA
Attached to a specific amino acid
Contains an anti-codon of three bases
tRNA’s anticodon will pair-up with RNA’s
codon.
Amino acid
Anti-codon
Reading a round genetic code:
For the first codon (G U A):
1. Find “G” in the middle of the wheel.
2. Follow that to “U” in the next outer
ring.
3. Follow that to the A in the third ring.
4. Read the name of the amino acid in
the last ring.
5. In this case G U A codes for Valine.
Reading a table genetic code:
For the first codon (G U A):
1. Find “G” on the left hand side.
2. Match the “G” with the “U” from
the top.
3. Follow that to the A in the third
ring.
4. Match both of these letters with
the right hand side.
5. In this case G U A codes for
Valine.
Step 4:
-The ribosome guides another tRNA to the mRNA codon.
Leucine
valine
mRNA “codons”
Step 5:
-The ribosome bonds the two amino acids together.
valine
Leucine
mRNA “codons”
Step 6:
-The first tRNA releases from the mRNA and its amino acid.
valine
Leucine
mRNA “codons”
Step 7:
-The ribosome moves to the next codon.
valine
Leucine
mRNA “codons”
Step 8:
-The ribosome guides another tRNA to the mRNA codon.
valine
Leucine
mRNA “codons”
valine
Step 9:
-The ribosome bonds the amino acids together.
valine
Leucine
mRNA “codons”
valine
Step 10:
-A tRNA releases from the mRNA and its amino acid.
valine
Leucine
mRNA “codons”
valine
Step 11:
-The ribosome moves to the next codon.
valine
Leucine
mRNA “codons”
valine
Step 12:
-The ribosome guides another tRNA to the mRNA codon.
valine
Leucine
mRNA “codons”
valine
Step 13:
-The ribosome bonds the amino acids together.
valine
Leucine
mRNA “codons”
valine
Step 14:
-The tRNA molecules detach from the mRNA and their amino
acids.
valine
Leucine
mRNA “codons”
valine
Step 15:
-The protein is now complete.
valine
Leucine
mRNA “codons”
valine