biology homework

1.-What is endocytosis? Please give an example.

2.- What happens to a red blood cells if they are exposed to an hypertonic environment? Why ?

3.- What is the difference between passive and a active transport? Please give examples.

4.- What is a plasmodesmata?

5.- Membranes are ________________________ because they let some, but not all, substances pass.

6.- What is pinocytosis ?

7.- What is a cotransport system ? Why is important?