Download TRANSLATION

Protein Synthesis:
Translation
How is mRNA “translated” into
a protein?
TRANSLATION
Process when the protein is
actually made
• Occurs at the ribosome in
the cytoplasm
• Uses an anticodon on the
tRNA to bring an amino acid to
the ribosome
5. mRNA leaves
the nucleus and
travels to the
ribosome in the
cytoplasm
REMEMBER:
DNA’s code is copied to mRNA in
codon groups.
A CODON is a grouping of three
nitrogen bases in mRNA that carry the
code for an amino acid.
U
C
A
G
codon
A
G
codon
Transfer RNA (tRNA)
amino acid
tRNA Has a cloverleaf shape
tRNA carries an
amino acid at one
end and
an anticodon at the
other end.
anticodon
ANTICODON
The anticodon the
complement to the mRNA
codon.
EX: mRNA codon:
AUG
tRNA anticodon: UAC
Anticodon
Codon
The tRNA also picks up the
amino acid that corresponds
to the mRNA codon
But how do we know which amino acid
corresponds to each codon?
Codon
AMINO ACID CHART
This chart is used to find the appropriate amino
acid using mRNA codons.
Second Base
C
A
G
U
Phenylalanine
Phenylalanine
Leucine
Leucine
Serine
Serine
Serine
Serine
Tyrosine
Tyrosine
Stop
Stop
Cysteine
Cysteine
Stop
Tryptophan
U
C
A
G
C
Leucine
Leucine
Leucine
Leucine
Proline
Proline
Proline
Proline
Histidine
Histidine
Glutamine
Glutamine
Arginine
Arginine
Arginine
Arginine
U
C
A
G
A
Isoleucine
Isoleucine
Isoleucine
Methionine
Threonine
Threonine
Threonine
Threonine
Asparagine
Asparagine
Lysine
Lysine
Serine
Serine
Arginine
Arginine
U
C
A
G
G
Valine
Valine
Valine
Valine
Alanine
Alanine
Alanine
Alanine
Aspartic Acid
Aspartic Acid
Glutamic Acid
Glutamic Acid
Glycine
Glycine
Glycine
Glycine
U
C
A
G
Third Base
First Base
U
What would
the amino
acid
the mRNA
codon UGG?
mRNAbe
codon
UGG is
thefor
amino
acid Tryptophan
TRANSLATION
mRNA at the ribosome in the cytoplasm
ribosome
mRNA
TRANSLATION
6. tRNA assists by bringing an
amino acid to the ribosome
7. tRNA matches its
anticodon with the
codon of mRNA to
place the amino acid in
the correct sequence
STOP
Peptide Bond
Peptide Bond
TRANSLATION
Stop Codon
A special codon called a STOP CODON marks
the end of the gene and protein synthesis.
STOP
TRANSLATION
Polypeptide Chain - A Protein
8. The amino acids bond with peptide
bonds and form a polypeptide chain or
protein.
amino
acid
peptide
bonds
polypeptide = protein
REVIEWING TRANSLATION
Protein is made
5. mRNA leaves nucleus, goes to
ribosome in cytoplasm
6. tRNA assists by bringing an amino
acid to the ribosome
7. tRNA matches its anticodon with
the mRNA codon, putting amino acids
in the correct sequence
8. amino acids bond, forming a
protein
click to play animation
TRY THIS!
Transcribe and translate this segment
of DNA:
TACACCTGCGCATAG