Module 4c Membrane Transport

Question 1

What is passive transport?

Answer 1

Transport across a membrane from area of high concentration to area of low concentration (requires no energy).

Low MW drugs have an easier time crossing membrane.

Uncharged and unionized compounds.

Question 2

What is active transport?

Answer 2

Transport of a drug across a concentration gradient. Require the aid of membrane bound protein to recognize drug transport. Needs ATP.

Used for charged compounds.

Question 3

Transport and Drug Distribution are affected by what two factors?

Answer 3

Size and Charge

Question 4

What are the sizes of small drugs?

What are the sizes of lipophilic drugs?

Answer 4

Small Drugs (<50 Da): Bulk Flow- can fit through the space of the phospholipid bilayer

Lipophilic Drugs (50-500 Da): Passive Transport

Question 5

What are the sizes of charged drugs?

Answer 5

Ionized Drugs (>50 Da): Active Transport