Pinocytosis and Phagocytosis

Question 1

What microfilament helps form the pseudopod?

Answer 1

Actin

Question 2

Describe the initiation of phagocytosis

Answer 2

Ligand coated antigen/particle binds phagocyte surface receptors. Pip2 phosphorylated to PIP3 by PI3 kinase.

Question 3

What happens when Phagosome is inside the cell?

Answer 3

The phagosome fuses with lysosome. Interior degraded. Probably glycosylation protects inner membrane.

Question 4

Initiation of Pinocytosis

Answer 4

Happens all the time.
Caveolae burrow into membrane, forms a cavern. Dynamin completed fusion. Nonspecific Endocytosis.
No recycling, goes straight to late endosome.

Question 5

Theory of Pinocytosis membrane balance

Answer 5

When there is too much membrane (lots of exocytosis) the membrane is very loose, not right. The caveolae have an easier time fitting into the membrane. Similar concept to the hydrolysis of GTP in Arf1 causing COPII to fall off in golgi-Ear transport.