golgi complex and membrane trafficking

Question 1

why do we need a secretory pathway

Answer 1

cells must be able to identify proteins and make sure theyre transferred to the correct location

Question 2

which proteins do not use secretory pathway

Answer 2

ones going to mitochondria and chloroplasts

Question 3

what is the sequence of events in secretory pathway

Answer 3

ER to Golgi then packaged into vesicles and sent to extracellular location

Question 4

describe the maintenance behind secretory pathway

Answer 4

can go in opposite direction
endosymbiosis into ER
return proteins back to earlier stages

Question 5

what is ER export

Answer 5

movement of subsatnces from ER to golgi

Question 6

describe the process of ER export

Answer 6

in ER:
- proteins folded and packaged into vessicles
(soluble proteins in lumen and transmembrane in membrane of vesicles)

vesicles budded off contain COPII coats

co protein coordinates forward movement to secretory pathway
forms vestibular tubular cluster at golgi complex

Question 7

what are the two specific ER exit signals

Answer 7

di acidic amino acids

di hydrophopbic

Question 8

describe di acidic amino acids signsl

Answer 8

on cystolic side
glu or asp
targets transmembrane proteins to golgi complex

Question 9

describe di hydrophobic signals

Answer 9

met

targets to transport to golgi complex

Question 10

describe ER retrieval

Answer 10

recylcing system of KDEL sequences
vestibular tubular cluster recognises KDEL
KDEL binds to receptors creating a budding membrane with a COPI coat

Question 11

describe the difference between COP1 and COPII

Answer 11

1 to ER

II to golgi

Question 12

describe the structure of golgi complex

Answer 12

cis golgi network
three cisterna- cis medial, trans
trans golgi network

Question 13

what is the golgi complex

Answer 13

processing factory of the cell

modifies proteins from ER

Question 14

describe physiology of golgi complex

Answer 14

series of flattened stacks that have lumen and surrounding membrane - cisterna

Question 15

what is the trans golgi network

Answer 15

distribution hub

proteins packaged into vesicles and sent out

Question 16

where does n linked glycosylation occur

Answer 16

in ER

further modification in golgi complex

Question 17

what is glycosylation

Answer 17

determines cellular destination

Question 18

what are the enzymes for addition and removal of sugars in glycosylation

Answer 18

glycosyltransferases

glycosidases

Question 19

what is o linked glycosylation

Answer 19

addition of sugar to serine/theranine residues

can only apply one sugar at a time

Question 20

where is o linked glycosylation common

Answer 20

in cytoplasmic / nuclear proteins

Question 21

what does o linked glycosylation do

Answer 21

acts as a signal to target correct location

Question 22

what are an example of sugar molecules involved in o linked glycosylation

Answer 22

fructose
glucose
mannose

Question 23

what are sphingomyelin and glycolipid made from

Answer 23

precursor cermide

Question 24

what is ceramide composed ofq

Answer 24

sohingosine and fatty acid

Question 25

what are 5 examples of golgi mediated PTM and where does it occur

Answer 25

``` sulfation of tyrosine residues-cis golgi phosphorylation- cis cisterna palmitoylation- medial cisterna proteolytic processing- trans cisterna oligomerisation- trans golgi ```

Question 26

what is the cisternal maturation model

Answer 26

recyling of enzymes through migrating and maturing throughgolgi structure

Question 27

what is the final job of the trans golgi network

Answer 27

targeting lysosome

Question 28

what do lysosomal protein targeting require

Answer 28

modification of n linked glycosylation protein to mannose-6-phosphate which is specific target to move proteins to the lysosome