7.9 Flashcards
Why is extocytosis important?
Allows cell to secrete waste, rebuilds cell membrane, cell to cell communication.
Define Constitutive Exocytosis
The regular secretion of molecules by vesicles from the golgi apparatus straight to the cell wall
How is Regulated Exocytosis different from Constitutive extocytosis
Regulated Exocytosis doesn’t happen until an out of cell signal is received. Only then will the vacuole secrete where needed. Regulated Exocytosis uses kiss and run fusion.
How do lysosomes help exocytosis
Some vesicles carrying waste for exocytosis bond with lysosomes and break down the materials before releasing them outside of the cell.
What are early endsomes?
membrane sacs found in the cytoplasm
Early endomes function?
They fuse with vesicles within the cell and help sort different molecules into the necessary spots
List the 5 steps in Exocytosis
- Trafficking
- Tethering
- Docking
- Priming
5.Fusion
First step of exocytosis
(Trafficking) First step in exocytosis. Vesicles are transported to the cell membrane
Second step of Exocytosis
(Tethering) Second step in exocytosis. Vesicles link and tether to the cell membrane
Third step of exocytosis
(Docking) Third step in exocytosis. The phospholipid bilayer of the vesicle and the cell membrane merge.
Fourth step in exocytosis
(Priming) Only occurs in regulated exocytosis. For signaling processes to occur modifications are needed to be made to the cell membrane before fusion
Final step in Exocytosis and what are the 2 methods?
(Fusion) Final step of exocytosis. 2 kinds. Complete fusion- Using ATP the vesicle fully forms to the cell membrane and creates a fusion pore to move the molecules out of the cell. Kiss and run fusion- Vesicles temporarily fuses with the cell membrane to release the molecules and then un attaches and goes back into the cell.
