synthesis of proteins and lipids

Question 1

phospholipids are synthesised in the

Answer 1

smooth ER

Question 2

cytosolic proteins are synthesised

Answer 2

in the cytosolic ribosomes and then released into the cytosol

Question 3

transmembrane proteins are synthesised

Answer 3

in the cytosolic ribosomes and then release a signal sequence which halts translation and directs the ribosome to dock on surface of ER. translation continues after docking and is then inserted into the membrane

Question 4

signal sequence is

Answer 4

short stretch of amino acids at on end of polypeptide chain that determines the eventual location of the protein in a cell

Question 5

secretory pathway

Answer 5

synthesis of secreted proteins begins at cytosolic ribosomes and is completed after the ribosomes have docked in the ER. the polypeptide of the secreted protein enters the lumen of the RER. undergo post translational modification as they move through discs of golgi apparatus and are packaged into secretory vesicles which move along microtubules and fuse with plasma membrane, releasing the proteins out of the cell.

Question 6

post translational modifications that can occur

Answer 6

addition of carbohydrate, proteolytic cleavage (used in secreted proteins to active them)