1. Do Now: Label the following: Sense strand Anti-sense strand
5’ end of RNA
3’ end of RNA
IB Topic 7.4- Translation

2. Structure of tRNA Clover-shaped Anticodon on one end
CCA on the other end, where amino acid will bind.

3. Hooking the amino acid onto tRNA
Involves a tRNA activating enzyme, and uses ATP for energy.
Involves a
Condensation
reaction

4. Degeneracy of amino acids
Some amino acids have more than one mRNA associated with them.

5. Ribosome structure Made up of protein and rRNA
Large subunit- made up of two molecules of rRNA and some proteins
2 binding sites for tRNA (A site and P site)
Small subunit- made up of one molecule of rRNA and some proteins
Binding site for mRNA

6. IB Topic 7.4- Translation
Binding Sites
A site: hold a tRNA carrying the next amino acid to be added to chain
P site: hold the tRNA carrying the growing polypeptide chain
E site: exit site

7. Other Translation terms to know
Polysomes
Ribosomes that are clustered together on the mRNA, creating several copies of the same polypeptide at the same time
Start codons
Found at the 5’ end of mRNA
AUG
Stop codons
Translation stops- A site is not copied
UAG, UAA, UGA

8. Direction of Translation
Occurs in 5’3’ direction with regard to the mRNA.
Because start codon is found on the 5’ end

9. Steps of Translation Initiation Elongation Termination Translocation:
mRNA , the first tRNA, and the ribosomal subunits come together
Elongation
A succession of tRNA’s add their amino acids to the polypeptide chain as mRNA is moved through the ribosome, one codon at a time
Termination
Ribosome recognizes the stop codon and polypeptide is terminated and release
Translocation:
Moving from one spot to the other.
Animation

10. Free vs. Bound Ribosomes
IB Topic 7.4- Translation
Free vs. Bound Ribosomes
Free ribosomes- synthesize proteins for use within the cell
Bound ribosomes- (rough er) synthesize proteins for secretion or for lysosomes.