exocytosis and endocytosis Flashcards
what are the functions of the ER
protein biosynthesis (rough)
lipid biosynthesis (smooth)
intracellular Ca2+ store
describe the structure of the ER
tubules and sacs developed from nuclear outer membranes
has a lumen
how does the ER undergo post translational modification
form disulphide bonds
proper folding
addition of carbohydrates
specificic cleaving
assemble multimeric proteins to be sent to Golgi
what are the different layers within the golgi apparatus
Cis Golgi Network:
Cis Cisterna
Medial Cisterna
Trans Cisterna
Trans Golgi Network
what are the different functions of the golgi
carbohydrate synthesis
post translational protein and lipid modification: phosphorylation, sulphation, glycosylation
ER product sorting for exocytosis
which cells have many golgi
secretory ex) goblet
what is an early endosome
organelle (vesicle) that receives substances form endocytosis
how can early endosomes become late endosomes
fuse with each other
early fuses with late
where are early endosomes found
under the plasma membrane
where are late endosomes found
near the nucleus
what is the function of a late endosome
sorting compartement for endocytic substances
ex) receptors recycles to membrane or lysosomes or a different domain of the membrane depending on their adresses
what is the function of a lysosome
digestion of products (recycling)
contains digestive enzymes for acid hydrolysis
describe the process of vesicle transport
- cargo molecules bind to -transmebranous receptors in the donor membrane
- curved coat proteins bind to cargo and dissociates membrane and forms a bud
- Dyamin released vesicles (pinches off)
- vesicles will uncoat and travel to recipient membrane idenitfies by
- surface markers (V snares) that are complementry to target membrane (t snares)
- the v and t snares wrap around each other to form a trans snare complex which locks the membrane together, locking and fusing the membranes
which curved coat protein is used for transport between the ER and Golgi
COPII
What do snares mediated
homolytic fusion of vesicles
how to Vesicular Tubular Clusters get to the golgi
move along microtubules by dyneins
what are the different pathways in exocytosis
- constitutive secretory pathway - trans golgi apparatus to the plasma membrane
no signals required
regulated secretory pathway
for specialises secretory cells like hormones, neurotransmitters, enzymes
how are non protein molecules secreted
ex) neurotransmitters at the axon
vesicle docks
priming occurs
Ca2+ signals for an intake action potential
membranes fuse
firing
how do toxins interfere with synaptic signalling and give some examples
cleave the trans snare complexes
so vesicles cannot dock
tetanus, botulinum
what is endocytosis and the different types
intake of molecules from the extracellular space
pinocytosis
phagocytosis
what is pinocytosis
non specific uptake
recycling of membrane
is receptor mediated
what is phagocytosis
interact with receptors
cytoskeleton rearanges to make pseudopods
phagosome forms
phagolysosome forms
what occurs to endocytosed vesicles (endosomes)
recycled by recycling endosomes
vesicles go to different parts of the cell membrane to spread the material (transytosis)
degradation cargo proteins send to late endosomes to mature into lysosomes
macromolecules are degraded to make new molecules
