Membrane Transport

Question 1

What are the different types of transport mechanisms?

Answer 1

Passive diffusion
Facilitated diffusion
Active transport
Vesicular transport (pinocytosis)
Cell to cell transport

Question 2

What are the 2 transport routes?

Answer 2

Transcellular and paracellular diffusion

Question 3

Describe passive diffusion

Answer 3

If the drug is too hydrophobic it will accumulate in the membrane moving very slowly

Question 4

What’s the purpose of increasing passive diffusion?

How is this done?

Answer 4

Improving membrane permeability of drugs - Removing polar functional groups (of drugs will allow it to diffuse across membranes more easily)

Question 5

Describe facilitated diffusion

Answer 5

Selective transport across membrane via transport proteins - For specific molecules

Question 6

What type of transport is used for facilitated diffusion?

Answer 6

Transport proteins - Channel (Aquaporins - Allow quick diffusion of H2O ), Carrier proteins

Question 7

Describe active transport

Answer 7

ATP to transport molecule against its conc grad

Allows cell to maintain its internal environment

Question 8

Describe Na/K-ATPase

Answer 8

Na/K pump - Transports ions across cell membrane against conc grads, ATP needed/Maintains resting potential of cells

Question 9

Describe co-transport

Answer 9

Cell membrane uses electrochemical gradient as energy
Transports 2 molecules/ions simultaneously using grad of one solute’s conc to force the other against grad
Single ATP pump can transport several other solutes

Question 10

What are the 2 types of glucose transporters?

Answer 10

Transporter facilitated passive diffusion (GLUT)

Co-transporter mediated transport Na/Glucose transporters (SGLT)

Question 11

Describe GLUT

Answer 11

Key in glucose diffusion across tissue barriers

Question 12

Describe SGLT

Answer 12

Key in glucose absorption from intestinal tract/renal tubules

Question 13

Describe the difference between symport and antiport co-transport

Answer 13

Symport - Transports 2 molecules in same direction

Antiport - 2 molecules in opposite directions

Question 14

Describe vesicular transport

Answer 14

Active movement of substances across a cell membrane via a vesicle

Question 15

Describe cell-to-cell transport

Answer 15

Gap junctions - Specialised connections, form narrow pore btw adjacent cells - Permit small molecules/ions to move from one cell to another

Question 16

Describe cardiac tissue in cell-to-cell transport

Answer 16

Extensive gap junctions - Allow rapid movement of ions btw cells = Helps tissue beat in rhythm