PROTEIN SYNTHESIS
NOTES #1
Review
What is transcription?
 Copying of DNA onto mRNA
 Where does transcription occur?
 In the Nucleus
 When copying DNA onto mRNA
there is no Thymine (T) instead
there is Uracil (U)
 A – U; G – C

More Review
What is Translation?
 The changing of mRNA into a
protein
 Where does Translation occur?
 In the Ribosome
 What is a codon?
 3 bases on mRNA
 What is an anticodon?
 3 bases on tRNA

Last of the Review
What type of RNA carries the amino
acids to the ribosomes?
 tRNA
 What is the start codon?
 AUG
 What are the stop codons?
 UGA, UAA and UAG

Codon Wheel or Codon Chart
Each codon (3 bases on mRNA) codes
for a particular amino acid
 You find which amino acid is coded for
by looking on one of the codon charts
 Codon Wheel – start from the middle
and work your way out
 Codon Chart – Start on the left side,
then the bottom (or top) and then the
right side

The Genetic Code (mRNA)
A
1st
Base in
Codon
G
Lysine
Lysine
Asparagine
Asparagine
Arginine
Arginine
Serine
Serine
Isoleucine
Methionine
Isoleucine
Isoleucine
Threonine
Threonine
Threonine
Threonine
A
G
U
C
Glutamic acid
Glutamic acid
Glycine
Glycine
Glycine
Glycine
Valine
Valine
Valine
Valine
Alanine
Alanine
Alanine
Alanine
A
G
U
C
‘Stop” codon
Tyrosine
Tyrosine
Tryptophan
Cysteine
Cysteine
Leucine
Leucine
Phenylalanine
Phenylalanine
Serine
Serine
Serine
Serine
A
G
U
C
Glutamine
Glutamine
Histidine
Histidine
Arginine
Arginine
Arginine
Arginine
Leucine
Leucine
Leucine
Leucine
Proline
Proline
Proline
Proline
A
G
U
C
A
G
U
C
Aspartic acid
Aspartic acid
“Stop” codon
“Stop” codon
U
C
2nd Base in Codon
3rd
Base in
Codon
Practice Using One of the
Codon Charts
 If
the codon is GCC, what is the
amino acid?
 Alanine
 If the codon is UGG, what is the
amino acid?
 Tryptophan
 If the codon is AGU, what is the
amino acid?
 Serine
More Practice Using One of the
Codon Charts
 Can
you go backwards?
 How many codons are there for
the amino acid proline?
4
 Name
 CCU,
 Name
 AGG,
the 4 codons for proline.
CCC, CCA, CCG
2 of the codons for arginine.
AGA, CGG, CGA, CGC, CGU
Protein Synthesis Practice
 If
one side of the DNA strand
is:
TACACCGGTCCATTTACT
 What is the complementary
(other) side of the DNA
strand?
ATGTGGCCAGGTAAATGA
Protein Synthesis Practice
 Using
the original DNA
strand:
TACACCGGTCCATTTACT
 Perform transcription – what
is the mRNA produced?
AUGUGGCCAGGUAAAUGA
Protein Synthesis Practice
 Break
the mRNA into codons
(groups of 3):
AUGUGGCCAGGUAAAUGA
 Perform Translation- what is
the protein produced?
Meth – Tryp – Pro – Gly – Lys (stop)
(start)
Another Protein Synthesis
Practice Problem
 If
DNA is:
TACAATGCCAGTGGTTCGCACATT
 What
is the mRNA?
AUGUUACGGUCACCAAGCGUGUAA
 What
is the protein made?
Meth-Leu-Arg-Ser-Pro-Ser-Val (stop)