Unit 1.2.b.ii

Question 1

What are synthesised in the ER

Answer 1

Lipids and proteins

Question 2

What is the difference between Rough ER (RER) and smooth ER (SER)?

Answer 2

Rough ER (RER) has ribosomes on its cytosolic face while smooth ER (SER) lacks ribosomes.

Question 3

Where are lipids synthesised

Answer 3

Lipids are synthesised in the smooth endoplasmic reticulum (SER) and inserted into its membrane

Question 4

Where does the synthesis of all proteins begin?

Answer 4

cytosolic ribosomes

Question 5

Where is the synthesis of cytosolic proteins completed and where are they stored?

Answer 5

Cyctosolic ribosomes and these proteins remain in the cytosol

Question 6

What is the function of transmembrane proteins?

Answer 6

To carry a signal sequence, which halts translation and directs the ribosome synthesising the protein to dock with the ER, forming RER. Translation continues after docking, and the protein is inserted into the membrane of the ER

Question 7

What is a signal sequence?

Answer 7

A short stretch of amino acids at one end of the polypeptide that determines the eventual location of a protein in a cell.