Exam 1

Question 1

What is transcellular diffusion vs. paracellular diffusion?

Answer 1

Transcellular diffusion is a route of molecule passage through the cell membrane, while paracellular diffusion is passage between the cells.

Question 2

Can ionized molecules or unionized molecules passively cross biologic membranes?

Answer 2

Unionized

Question 3

What are the three physical properties of a xenobiotic that affect its ability to cross the cell membrane?

Answer 3

Polarity, size, and charge

Question 4

What are the three main routes by which molecules cross biologic membranes?

Answer 4

Simple diffusion, facilitated diffusion, and active transport

Question 5

What are the two main families of transporters for xenobiotics and what form of transport do they use?

Answer 5

1. ATP-binding cassette (ABC) transporter family - active transport
2. Solute carrier (SLC) family - facilitated diffusion