The protein secretory pathway

Question 1

where are proteins intended for export from the cell synthesised

Answer 1

at the ribosomes attached to the rough endoplasmic reticulum

Question 2

function of the rough er

Answer 2

the proteins move through the lumen of the rough er towards the golgi apparatus, this also asists with protein folding

Question 3

structure of the golgi body

Answer 3

stack of 4-8 flattened sacs called cisternae, cis flaces the rough er, medial is the middle, trans faces away from rough er

Question 4

function of the golgi appartus

Answer 4

the proteins move through tthe cisternae as resident enzymes add or remove sugars and add phosphate or sulphate groups, these modifications act as shipping labels, golgi packages proteins into secretory vesicles

Question 5

once a vesicle is relased from the golgi what happens

Answer 5

the cargo proteins bind to specific embrane bound receptor proteins withi the vesicles, changing their shape, creating a ‘shipping label’

Question 6

how do vesicles reach the membrane

Answer 6

over short distances, they can diffuse, over long distances they are carried by motor proteins along the microtubuules of the cytoskeleton

Question 7

what happens once tthe vesicles reach the cell membrane

Answer 7

they fuse with it and let the protein into the extracellular fluid