Chapter 4

Distinguish between a substance moving down a concentration gradient and a substance moving against a concentration gradient.

What is vesicle-mediated transport, and how does endocytosis differ from exocytosis?

What are the differences between phagocytosis and receptormediated endocytosis?

Explain, in general terms, what happens in each step-reception, transduction, and induction-of a signal-transduction pathway.