1. Translation
PROTEIN SYNTHESIS

2. Transcription = Nucleic acid sequence (a gene)  an identical copy of the Nucleic acid sequence (mRNA)
Translation = Nucleic acid sequence (mRNA)  a sequence of Amino acids (a protein).
How do we decode the sequence of nucleotides on mRNA and turn it into a sequence of amino acids (a protein)?

3. How many different amino acids are there?
So can one base code for one amino acid ex. Can adenosine (the base) code for tryprophan (an amino acid)?
Can two bases?
What about three?

4. Meet tRNA … “the decoder”
There are 64 species of tRNA, each species recognizes the code for an amino acid or a start or stop signal
Why 64?

5. Codons and Anticodons
A codon is a group of three nucleotides on an mRNA molecule
An Anticodon is the complimentary group of three nucleotides on a tRNA
When the codon is recognized by the complimentary anticodon on the tRNA the correct amino acid corresponding to that codon is made available.

6. 4 Components used in Translation
mRNA- the message to be translated into protein.
Amino acids- the building blocks that are linked together to form the protein.
Ribosomes- the “machines” that carry out translation.

7. tRNA (transfer RNA)- brings an amino acid to the mRNA and ribosome.
One end of a tRNA molecule has an anticodon that complements with an mRNA codon.
The other end has a specific amino acid.
A tRNA molecule with a particular anticodon always carries the same type of amino acid.

8. How does translation occur?
The ribosome binds to the mRNA molecule.
The tRNA with the anticodon that complements the first codon on the mRNA binds to the first site on the ribosome.
Another tRNA with the anticodon that complements the second codon on the mRNA binds to the second site on the ribosome.

9. A peptide bond forms between the first two amino acids.
The first tRNA leaves, and the ribosome moves along the mRNA to the next codon.
The next tRNA brings in the next amino acid, and a peptide bond is formed between this amino acid and the growing amino acid chain.
The process continues with the ribosome moving along the mRNA molecule and the amino acids linking together until a STOP codon is reached.

10. The CODE of translation

11. mRNA nucleotides are translated in groups of 3 called codons.
AUGCACUGCAGUCGAUGA
CODONS

12. Each codon codes for a specific amino acid
Each codon codes for a specific amino acid. 20 different amino acids can be used in different combinations to form a protein.
For example:
mRNA codon amino acid
AAU asparagine
CGC arginine
GGG glycine

13. Amino Acid sequence determines the 3-D protein shape
Interactions between amino acids cause folding and bending of the chain
Examples:
positive (+) and negative (-) parts of amino acids are attracted to each other.
hydrophobic regions are attracted to each other
Folding
Structure levels
structure.swf

14. How is the amino acid sequence determined?
The mRNA
Each codon is a code for one amino acid
DNA sequence: T A C C G A G A T T C A
mRNA sequence: A U G G C U C U A A G U
amino acid sequence: Met -- Ala -- Leu -- Ser

15. U C A G
UUU Phenylalanine (Phe)
UCU Serine (Ser)
UAU Tyrosine (Tyr)
UGU Cysteine (Cys)
UUC Phe
UCC Ser
UAC Tyr
UGC Cys
UUA Leucine (Leu)
UCA Ser
UAA STOP
UGA STOP
UUG Leu
UCG Ser
UAG STOP
UGG Tryptophan (Trp)
CUU Leucine (Leu)
CCU Proline (Pro)
CAU Histidine (His)
CGU Arginine (Arg)
CUC Leu
CCC Pro
CAC His
CGC Arg
CUA Leu
CCA Pro
CAA Glutamine (Gln)
CGA Arg
CUG Leu
CCG Pro
CAG Gln
CGG Arg
AUU Isoleucine (Ile)
ACU Threonine (Thr)
AAU Asparagine (Asn)
AGU Serine (Ser)
AUC Ile
ACC Thr
AAC Asn
AGC Ser
AUA Ile
ACA Thr
AAA Lysine (Lys)
AGA Arginine (Arg)
AUG Methionine (Met) or START
ACG Thr
AAG Lys
AGG Arg
GUU Valine Val
GCU Alanine (Ala)
GAU Aspartic acid (Asp)
GGU Glycine (Gly)
GUC (Val)
GCC Ala
GAC Asp
GGC Gly
GUA Val
GCA Ala
GAA Glutamic acid (Glu)
GGA Gly
GUG Val
GCG Ala
GAG Glu
GGG Gly

16. Your turn Decoder construction-DNA Bingo
Translation exercise (Find the secret message)
Genes to proteins-practice worksheet. or
Complete the “Translation Practice” worksheet