1. Honors Biology Monkemeier Friday, January 18, 2019
Steps of Translation
Honors Biology
Monkemeier
Friday, January 18, 2019

2. Initiation
Large subunit and small subunit of the ribosomes come together.
When the subunits come together they form a “stage” with 2-3 “seats”
mRNA threads itself in between the large and small subunits.
A tRNA carrying Methionine checks its anticodon to the codon on the mRNA. The anticodon and codon are complementary to each other.

3. Initiation – What is not shown?

4. Initiation Complete

5. Elongation
Another tRNA carrying an amino acid matches its anticodon complementary to the codon on the mRNA.
A peptide bond is formed between methionine and the new amino acid.
The Ribosome moves over one codon on the mRNA.
The original tRNA carrying methionine goes away.
Another tRNA carrying an amino acid comes in and matches its anticodon complementary to the codon on the mRNA (newly exposed)
A peptide bond forms between the two amino acids.
The ribosome moves over one codon
PROCESS CONTINUES

6. Elongation

7. Termination A stop codon appears in the “A” site on the ribosome.
tRNA carrying the polypeptide falls off.
The large and small subunits of the ribosome break apart.
A newly formed polypeptide strand is formed.

8. Protein Formation
Remember that there are four levels of protein structure.
Translation forms the first level of protein structure – the polypeptide chain
Secondary structure involves hydrogen boding of the chain to form alpha helix or beta pleated sheet
Tertiary structure includes more bonding between the chain – Ex: Sulfur bridges
Quarternary structure: several chains together.