1. Whole process
Step by step- from chromosomes to proteins

2. Translation PROTEIN SYNTHESIS Today’s Objective:
By the end of the class today you will be able to translate a sequence of DNA into the corresponding amino acid chain.

3. Information flow from DNA to trait
Observed trait
DNA
protein
Made by ribosomes outside of nucleus
Stored in nucleus

4. Information flow from DNA to trait
messenger
RNA
Observed trait
DNA
protein
Made by ribosomes outside of nucleus
Stored in nucleus
Transcription

5. Information flow from DNA to trait
messenger
RNA
Observed trait
DNA
protein
Made by ribosomes outside of nucleus
Stored in nucleus
Translation

6. mRNA information  protein
messenger
RNA
protein
Translation is the process used to convert mRNA information into proteins.
- also known as “protein synthesis”
Note: mRNA does not become a protein, the information on mRNA is “read” and ribosomes assemble proteins from this code

7. 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.

8. 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.

9. 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.

10. 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.

11. The CODE of translation

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

13. 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

14. 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

15. 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

16. 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

17. Your turn
Complete the “Translation Practice” worksheet