T3L3 Rough ER and Golgi

Question 1

Describe the structure of the rER (detail)

Answer 1

• system of membrane bound sacs
• has enzymes in the membrane and the lumen that are made by the ribosomes

Question 2

Describe the role of the rER in protein folding and transport/secretion

Answer 2

• folds protein into 3D shape
• modifies proteins

Question 3

What happens when proteins leave the rER

Answer 3

Proteins are packaged into vesicles to go to other parts of the cell (normally the golgi)

Question 4

Describe the structure of the Golgi

Answer 4

Non-continuous sacs. Made of side by side cisternae. Proteins move between the cisternae through vesicles.

Question 5

What happens to proteins in the golgi and thereafter

Answer 5

-Modification (+ lipid and carbohydrate chains
- Proteins are packaged inti vesicles for delivery to membrane or lysosomes
- Lysosomes also made in golgi.

Extracellular enzymes are secreted via exocytosis

Question 6

Describe the full journey of proteins through the cell

Answer 6

Polypeptide chain grows from the ribosome into the lumen of the rER

In lumen of rER the protein folds into its tertiary structure (+ some modification)

Protein is packaged into a vesicle and goes to the golgi apparatus

It goes through the cisternae of the gogli apparatus being modified adding lipids/carbohydrates

It is then packaged into secretory vesicles to leave the cell via exocytosis