1. PROTEIN SYNTHESIS
THE DETAILS

2. TRANSLATION: The Details
Process that occurs after transcription.
Occurs in the cytoplasm, with the help of ribosomes and transfer RNA.

3. TRANSLATION: The Details
Translation refers to putting something into a different language – the message on the mRNA will be translated into a polypeptide chain

4. The Ribosome Consists of a large and small subunit.
2 subunits bind to mRNA clamping it between them.

5. The Ribosome Moves along the mRNA in the 5’3’ direction.
Ribosome reads triplets of bases from the mRNA (codons)

6. Fig 2 pg 250

7. Transfer RNA (tRNA)
delivers aa’s to a polypeptide building site (the ribosome)
Single stranded
looks like a clover leaf
Anticodon at one end recognizes mRNA codon

8. Transfer RNA (tRNA)
Opposite end of tRNA carries the corresponding amino acid.
tRNA recognizes mRNA when complementary bases pair between the codon and anticodon

9. Fig 3 pg 251

10. Transfer RNA (tRNA)
Question: What is the anticodon found on the tRNA carrying tyrosine?
Question: What amino acid is found on the tRNA with an anticodon of CAU?

13. Every tRNA carries one specific aa

14. TRANSLATION Steps INITIATION ELONGATION TERMINATION POST-TRANSLATIONAL MODIFICATION PROTEIN animation

15. TRANSLATION INITIATION
mRNA exits the nucleus after modifications and enters the cytoplasm.
Ribosomes recognize 5’ cap & bind to mRNA
ribosome starts translating at the start codon AUG

16. TRANSLATION INITIATION
the start codon ensures that the correct reading frame is used by the ribosome
AUG codes for methionine, therefore every pr- starts with the aa methionine

17. ribosomes have 2 sites that bind tRNA:
A (acceptor) site – where tRNA brings in new aa
P (peptide) site – where peptide bonds form between aa’s in growing polypeptide

18. Pg 252
First tRNA is brought into P site – carries Met because the start codon is AUG

20. Pg Elongation
2nd tRNA enters A site

21. A peptide bond forms between the 2 aa’s
Pg 252
A peptide bond forms between the 2 aa’s

22. Pg 252
Ribosome translocates one codon over. tRNA brings in the appropriate aa into
A site.

23. 2) ELONGATION
tRNA’s are released from the P site
tRNA is recycled by aminoacyl-tRNA synthetase which adds their corresponding aa to them

24. Elongation Diagram

25. 3) TERMINATION
when the ribosome reaches one of 3 stop codons (UGA, UAA, or UAG) the 2 subunits disassociate.
there is no corresponding tRNA for the stop codon

26. The process is repeated until the ribosome reaches a stop codon.
Pg 252

27. 3) TERMINATION
A pr- called a release factor recognizes the ribosome has stalled and helps the polypeptide chain release from the ribosome.
the polypeptide chain may be altered in the cytoplasm

28. 2 ribosome subunits fall off mRNA
Pg 252

29. Termination Diagram

31. Translation: Simplified translation animation

32. OVERALL: In Detail

33. OVERALL: Less Detail