7A Flashcards
(18 cards)
Vesicle traffic
is a membrane-bound intermediate between 2 different membrane compartments.
taking protein from one membrane the donor to the other target
how transport?
Transport by taking pieces of membrane with them in vesicles. lipid bilayer of the vesicle donor merge with the lipid bilayer of the the target compartment.
does vesicles pass and lipid bilayer to transfer protein?
no, because it just takes the protein by merging the vesicles from one membrane to another. it doesn’t have to go through transport of bilayer.
Topology of the cell?
continuity and ability to exchange without crossing the membrane.
2 locations must have same topology if a molecule cab be transported between 2 locations using only vesicle fusion or fission. they don’t require a membrane transport pore or translocator.
how many types of vesicle traffic in the plasma membrane>
endocytosis and exocytosis
whast exocytosis?
when a vesivle from inside of a cell will fuse to the plasma membrane
inside cell do not
plasma membrane target
endocytosis
when the protein enters the cell from an extracellular environment. such as iron,protein and mroe
vesicle transport process?
donor to target movment
vesicle formation (budding)
vesicle fission
whats donor to target movment?
starts at ER as a donor compartment
proteins can move to different destinations:
golgi, lysosomes, cell exterior, plasma membrane
whats the vescile formatoon or budding?
begin with donor comparment containg protein, to be moved
- forms buble like structure from donor membrane
- include:
- integral membrane proteins (embedded in membrane)
- soluble proteins )in vesicle interior)\
- process requires energy and specific protein
What is vesicle fusion?
-vesicle merges with target compartment
- lipid bilayer of vesicle and target membrane fuse
- proteins maintain same topology throughout transport
-delivers cargo to new location
Prtoeyn coats, types and functions?
4 types of coat protein:
COP2 functo at ER
COP1 function at GOLGI cisternae
clathrin: function at plasma membrane and golgi
retromer: early endosomes
coat protein functions?
-provide energy and machinery for membrane budding
- select specific cargo proteins for transport
- enable membrane bending and cutting
- ensure selective transport of needed materials
vesicle transport pathways?
biosynthetic pathway
exocytosis
endocytosis
biosynthetic pathway
moves protein from ER to other organells
including golgi, plasma membrane, endosomes, and lysosomes
exocytosis
releases materials to cell exterior\
examples
- neurotransmitters, enzymes, insulin
endocytosis
takes in materials from outside of cell
transport vitamins, nutrients, cholesterol
can lead to lysosome degradation or other cellular locations
maintaining organelle identity
- despite constant membrane flow, organelles maintain distinct identities.
- specific protein markers determine organelle identity
-controls what can be imported and exported from each compartment.
