1. Nucleus
Cytoplasm

2. Nucleus
Cytoplasm

3. Nucleus
DNA
Cytoplasm

4. T
A
C
A
G
G
A
G
T
C
A
G
A
C
T
A
T
G
T
C
C
T
C
A
G
T
C
T
G
A

5. RNA
Polymerase
T
A
C
A
G
G
A
G
T
C
A
G
A
C
T
A
T
G
T
C
C
T
C
A
G
T
C
T
G
A
Promoter Region

6. G
G
A
G
T
C
A
G
A
C
T
T
C
C
T
C
A
G
T
C
T
G
A
A
T
G
A
C
A
T
RNA
Polymerase

7. A U
C
T
G
T
C
A
G
A
C
T
T
C
A
G
T
C
T
G
A
A
T
G
T
C
C
A
G
G
A
C
A
T
RNA
Polymerase

8. A U
C
G
A
G
C
A
G
A
C
T
A
G
T
C
T
G
A
A
T
G
T
C
C
T
C
T
G
A
G
G
A
C
A
T
RNA
Polymerase

9. A U
C
G
A
G A G
A
C
T
C
T
G
A
A
T
G
T
C
C
T
C
A
G
T
G
A
C
T
G
A
G
G
A
C
A
T
RNA
Polymerase

10. A U
C
G
A
G A G U C
T
G
A
A
T
G
T
C
C
T
C
A
G
T
C
T
C
A
G
A
C
T
G
A
G
G
A
C
A
T
RNA
Polymerase

11. A U
C
G
A
G A G U CA
G
T
C
A
G
A
C
T
G
A
G
G
A
C
A
T
RNA
Polymerase
A
G
T
C
T
G
A
C
T
C
C
T
G
T
A

12. Nuclear Pore
Nucleus
Cytoplasm
mRNA

13. Amino
Acids
Small Subunit
rRNA
tRNA
Large
Subunit
Anti-codon
A
G
T
C
T
G
A
C
T
G
Codon
C
C
T
C
A
A
T
T
Start
codon
Stop
codon

14. Peptide Bond
A
A
G
T
C
T
G
G
C
G
T
C
C
T
A
G
T
A

15. A
C
T
G
T
T
G
T
C
A
G
A
C
C
T
G
T
A

16. A
G
G
A
G
T
C
T
C
A
C
T
C
C
T
G
T
A

17. A
G
T
C
T
G
A
C
T
C
C
T
G
T
A

18. A
G
T
C
T
G
A
C
T
C
C
T
G
T
A

19. Cytoplasm

20. Summary
• The first part of protein synthesis is transcription. It starts when mRNA
strands are transcribed in the nucleus. The strands are created from a
DNA template strand with the help of RNA polymerase. This mRNA
strand leaves the nucleus through the nuclear pores. The second part
of protein synthesis is translation, which occurs in the cytoplasm and
needs ribosomes. A small ribosome subunit attaches to the bottom of
the mRNA strand, and a large ribosome subunit attaches to the top of
the mRNA. Then the synthesis can begin, the ribosome "reads" the
mRNA and tRNA brings the right amino acid. Then the anticodon
matches with a codon. Then another anticodon comes along and then
the next so on and so forth. Then before the tRNA leaves the ribosome
polymerase creates a peptide bond between the amino acids. Then the
tRNA leaves the ribosome, leaving the amino acid behind. This process
repeats itself until it reaches a stop codon. Then the amino acid chain
called a polypeptide, is released into the cytoplasm as a protein.