1. Translation
The sequence of nucleotide bases in an mRNA molecule is a set of instructions that gives the order in which amino acids should be joined to produce a polypeptide.
The forming of a protein requires the folding of one or more polypeptide chains.
Ribosomes use the sequence of codons in mRNA to assemble amino acids into polypeptide chains.
The decoding of an mRNA message into a protein is a process known as translation.

2. Steps in Translation
Messenger RNA is transcribed in the nucleus and then enters the cytoplasm for translation. The mRNA then goes to the ribosomes for translation to begin.

3. The Roles of tRNA and rRNA in Translation
Ribosomes are composed of roughly 80 proteins and three or four different rRNA molecules.
These rRNA molecules help hold ribosomal proteins in place and help locate the beginning of the mRNA message.
They may even carry out the chemical reaction that joins amino acids together.

4. Ribosomes consist of two subunits.
The large subunit has three binding sites for tRNA.
The small subunit binds to mRNA.

5. Ribosome Structure
The ribosome is a very complicated organelle made of two separate pieces that come together to get the job done.
The large subunit, which has three sites for the tRNAs, named the E site, P site, and A site (remember “EPA” or "APE")
A: Arrival
P: Polypeptide (is created)
E: Exit

6. Steps in Translation
Each tRNA molecule carries just one kind of amino acid.
In addition, each tRNA molecule has three unpaired bases, collectively called the anticodon—which is complementary to one mRNA codon.
The tRNA molecule for methionine has the anticodon UAC, which pairs with the methionine codon, AUG.

7. Amino acids are linked to become a protein.
A tRNA carrying an amino acid is charged
When the tRNA picks up an amino acid, it is charging

8. Steps to Translation
Translation, like transcription, is a 3 step process:
Initiation
Elongation
Termination
Goal: To translate the mRNA code into a protein.
Each triplet codon must be read from the mRNA and used to add the appropriate amino acid to the polypeptide.

9. Steps in Translation
Translation begins when a ribosome attaches to an mRNA molecule in the cytoplasm.
As the ribosome reads each codon of mRNA, it directs tRNA to bring the specified amino acid into the ribosome.
One at a time, the ribosome then attaches each amino acid to the growing chain.

10. Initiation
The small ribosomal subunit binds to the mRNA at the 5' end of the mRNA molecule.
The initiator tRNA
Has methionine as an amino acid
Has an anticodon that is complementary to the start codon on mRNA (normally AUG).
This anticodon (normally UAC) binds to the mRNA.
The large ribosomal subunit binds to the tRNA at the P site.
This creates the the initiation complex.

11. Initiation

12. Elongation
The ribosome has a second binding site for a tRNA molecule for the next codon.
If that next codon is UUC, a tRNA molecule with an AAG anticodon brings the amino acid phenylalanine into the ribosome.

13. Elongation
The ribosome helps form a peptide bond between the first and second amino acids—methionine and phenylalanine.
At the same time, the bond holding the first tRNA molecule to its amino acid is broken.

14. Elongation
Codon recognition: the codon in the A site of the ribosome pairs with the appropriate tRNA molecule.
Peptide bond formation: the two amino acids are linked.
Translocation: The tRNAs in the P and A site move left. ◾A moves to P.
P moves to E.
The tRNA in the E site exits the ribosome.

15. Elongation
That tRNA then moves into a third binding site, from which it exits the ribosome.
The ribosome then moves to the third codon, where tRNA brings it the amino acid specified by the third codon.

16. Termination
The polypeptide chain continues to grow until the ribosome reaches a “stop” codon on the mRNA molecule.
When the ribosome reaches a stop codon, it releases both the newly formed polypeptide and the mRNA molecule, completing the process of translation.

17. Termination
Occurs when one of the three stop codons (UAA, UAG, UGA) arrives in the P site.
A release factor binds to the A site, causing the whole thing to fall apart.
The large and small ribosomal subunits separate from each other and from the mRNA.
The new protein is released and can now fold into its 3D shape and get to work in the cell

18. Translation Errors
The ribosome moves along the mRNA exposing the codons to be translated – this is the reading frame 
Frame-shift mutation results if initiation is shifted over from the reading frame by one or two nucleotides (alternate initiation site) or due to errors during splicing of the exons (insertion or deletion)

19. Signal Sequence
signal sequence - short (5-30 amino acids long) at the end of the newly synthesized polypeptide chain
Directs the polypeptide chain into the endoplasmic reticulum or other organelle for processing, packaging, and transport around or out of the cell

20. Protein Processing
After translation on ribosomes in the cytosolic compartment all proteins are processed either in the cytosol or in the ER/Golgi system. 
The initial stages of protein processing involving folding. 
folding of proteins takes place through interaction with chaperone proteins (they hold the polypeptide chain and aide in folding)
Proteins that are not properly folded are destroyed.  In the cytosol compartment they are tagged with ubiquitin and destroyed by proteasomes

21. Protein Processing