L3 - Active membrane transport

Question 1

Active membrane transport

Answer 1

Movement against chemical or electrochemical gradient
Requires energy
Via primary or secondary active transporters

Question 2

Primary active transport (Na+ pump)

Answer 2

• Each cycle: 3Na+ out, 2 K+ in against conc gradient
• Uses up significant amount of ATP
• Establishes membrane gradients

Question 3

Secondary active transport

Answer 3

• Uses established Na+ gradient to pump other solutes against their gradients
• Movement of Na+ down conc gradient provides energy

Question 4

Antiporter

Answer 4

Na+ comes into cell
Other solute goes out

Question 5

Symporter

Answer 5

Na+ and other solute both go into cell

Question 6

Types of active transport

Answer 6

1. Primary (Na+ pump)
2. Secondary (symporter, antiporter)

Question 7

Vesicular transport

Answer 7

Exocytosis
Endocytosis
Transcytosis

Question 8

Exocytosis

Answer 8

Vesicle forms in cell, comes in close contact with membrane, substance gets released
Requires ATP
e.g. release of hormones

Question 9

Endocytosis

Answer 9

Membrane creates vesicle by surrounding subtance, brings it into cell
- Receptor mediated
- Phagocytosis
- Bulk-phase
Requires ATP

Question 10

Receptor mediated

Answer 10

surface of emmbrane is activated to form pits

Question 11

Phagocytosis

Answer 11

membrane extends out and gathers substances
larger than receptor-mediated

Question 12

Bulk-phase

Answer 12

solutes settle onto membrane, depression formed, vesicle formed.