Production & Secretion Of Proteins

Question 1

Give the step by step process of the production & secretion of proteins

Answer 1

1. Nucleus contains the gene for the protein -> it’s the site of transcription (DNA -> mRNA)
2. Protein synthesis TRANSLATION (mRNA -> amino acid chain) takes place on the ribosomes often on the rough Endoplasmic reticulum (rER)
3. The protein is transported to the Golgi apparatus / body in a vesicle
4. The Golgi body modifies the protein eg adds a carbohydrate group -> glycoprotein
5. Protein is packaged into a golgi vesicle
6. Vesicle is transported to the cell surface membrane
7. Exocytosis - vesicle fuses with the membrane eg extra cellular enzymes

Question 2

Making a protein (school definition )

Answer 2

1. The nucleus is the site of the ribosome and mRNA manufacture (copy of the protein gene)
2. Ribosomes on the RER make proteins to be secreted ( free ribosomes) make proteins to stay in the cell
3. The proteins are transported from the RER to the Golgi body by vesicles
4. Golgi body further processes the proteins (may add sugar chain)
5. Vesicles containing proteins are ‘pinched off’ the Golgi body and moves towards the plasma membrane
6. Vesicles fuse with the plasma membrane and undergo exocytosis

Question 3

Draw the protein production and secretion diagram

Answer 3

Pg 13