Process of the synthesis and secretion of proteins from the cell

Question 1

What is step one of this process?

Answer 1

Nucleus contains the DNA which is copied (during transcription) to produce RNA

Question 2

What is step two of this process?

Answer 2

Nucleus pores in the nucleus envelope allow mRNA molecules to leave the nucleus
Attach to the ribosomes in the cytoplasm or on the RER

Question 3

What is step three of this process?

Answer 3

Protein synthesis occurs on ribosomes (which are composed of rRNA protein and synthesized in the nucleolus)

Question 4

What is step four of this process?

Answer 4

Polypeptides are moved through the RER and are packaged in vesicles
The vesicles bud off the RER & carry the polypeptides to the Golgi body

Question 5

What is step five of this process?

Answer 5

The vesicle fuses with the membranes and sheds its contents into the Golgi body
Here the protein is modified
At the other end of the Golgi body, vesicles containing the modified proteins bud off

Question 6

What is step six of this process?

Answer 6

They may be secretory vesicles which carry the proteins to the cell membrane for secretion by exocytosis
Alternatively these may be lysosomes, containing digestive enzymes which will be used within the cell