Cell Trafficking

Question 1

_ is the distribution center for proteins and lipids from the ER to vexicles and plasma membrane

Answer 1

golgi

Question 2

what are the posttranslation events in the golgi

Answer 2

addition of N-oligosachrides to asparginine

addition of O-oligosacchrides on serine and threonine

addition of mannose 6-phospahte to proteins

Question 3

_ are the sorting centers for material outside of the cell or from the golgi sending it to lysosomes for destruction or back to the golgi for further use

Answer 3

endosomes

Question 4

what is I cell disease

mutation?

failure in?

Answer 4

inclusion cell disease aka mucolipidosis type II

that is an inherited lysosomal storgae disease (AR)

mutation in N-acetylglucosaminyl-1-phosphotransferase

failure in phosphorylating mannose residues on glucoproteins in the golfi so enzymes are secreted extracellularly instead of eliminated via lysosomes

the lysosomes are decifent in digestive enzymes and inculsion bodies form inside of the lysosomes

Question 5

symptoms of Inclusion cell disease

Answer 5

coarse facial features, gingival hyperplasia, corneal clouding, restricted joint movement, increased plasma levels of lysosomal enzymes

fatal in childhood

Question 6

what is a signal recognition particle

Answer 6

a protein that is in the cytosol that tranfers ribosomes to the RER

*def= accumulation of proteins in the cytosol

Question 7

COP I vesicular traficking

Answer 7

golgi to golgi (retrograde)

cis golgi to RER

Question 8

COP II vesicular trafficking

Answer 8

ER to cis GOGI (retrograde)

Two steps foward (anterograde) one step back (retrograde)

Question 9

clathrin trafficking

Answer 9

trans-golgi to lysosomes, plasma membrane, and endosomes

Question 10

what are the three types of signaling

Answer 10

autocrine (self)
paracrine (neighboring)
endocrine (through the blood stream)

Question 11

what are the steps of a cell signaling pathway

Answer 11

reception (receptor binds to a ligand)
transudction (change in reception, 2nd messenger)
Cell response

Question 12

what are the cell receptors (most common)

Answer 12

G protein, enzyme couples, ion channel receptors

g protein- 7 transmembrane that avtivates G proteins

Question 13

what happens when a ligand binds a g protein coupled receptor

Answer 13

GDP is exchanged for GTP on the alpha subuit which activates the protein and seperates from the beta and gamma subunits and it is not free to interact with other proteins

GDP is the resting state

Question 14

what are the three types of G proteins ?

Answer 14

Gq, Gi, Gs

Question 15

Gq protein activates what

Answer 15

phospholipase C—> DAG and IP3

IP3 goes into the ER and releases calcium into the cytoplasm and depolarization

DAG binds to PKC (relies on Ca+ to activate)

PKC adds phosphate groups to proteins and activates them

Question 16

protein Gs activates what

Answer 16

adneylate cyclase - takes ATP and removes 2 phosphate groups to create CAMP

CAMP binds PKA at the regulatory subunit

regulaltory and catalytic subuit of PKA dissociate and the catalytic subuit will phosphorylate proteins

Question 17

Gi inhibition

Answer 17

negative feedback on G3

inhibits adenylate cyclase

Question 18

what is an enzyme coupled receptor

Answer 18

single pass transmembrane protein with intrinsic enzyme activity

receptor domain and eznyme domain (protein kinase that phosphoylates the receptor domain)

Question 19

what are the 3 main types of enzyme couple receptors

Answer 19

1. Receptor tyrosine kinase: dimerize and cross phophorylate
2. tyrosine kinase associated receptor- cytoplasmic tyrosine kinase (no intrinsic ability
3. receptor serine/threonine kinase: Type 1 and Type 2 ,type 2 activates type 1, type 1 will phosphorylate other proteins.

Question 20

what are ion channel receptors

Answer 20

usually closed, but bind to ligands and open up; allow ions to flow down their gradient and trigger a cellular response

Question 21

water channel

Answer 21

aquaporins

Question 22

bulk transport

Answer 22

endocytosis and exocytosis

need ATP to work

Question 23

endocytosis types

Answer 23

phagocytosis- WBC; phagolysosome
pinocytosis- vesicle (takes in solutes), kinesin and dyenin
receptor mediated endocytosis- LDL (clathrin coated pits)- endosome

endsome sepreates the receptor and the ligand (receptor recycling)

Question 24

exocytosis starts where

Answer 24

in the golgi apparatus

takes proteins, lipids and hormones to vesicles