(Trans)membrane Transport

Question 1

Membrane Potential

Answer 1

Total charge difference between inside and outside of the cell

Question 2

Resting (state) potential

Answer 2

Potential when cell is at rest

Question 3

Transport protein

Answer 3

Integral (almost always multi-subunit) protein

Has dock/binding site at center

When conformation facing outside, molecule enters and binds to inside, inducing conformational change

Question 4

Ion channels

Answer 4

FASTER

“Pores” that open to allow ions to pass through - usually open only in response to a signal e.g. hormone of voltage change

Question 5

“Other” (non-ion) transport proteins

Answer 5

SLOWER

Specialized carriers that provide a pathway for larger, polar molecules - generally junction all the time

Question 6

Uniport

Answer 6

One molecule active transport

Question 7

Symport

Answer 7

Two or more molecules going in same direction (active transport)

Question 8

Antiport

Answer 8

At least two molecules going in opposite directions (active transport)

Question 9

Direct active transport

Answer 9

Aka PRIMARY

Uses energy from ATP hydrolysis

Question 10

Indirect active transport

Answer 10

Aka SECONDARY

Energy from diffusion of another molecule down its concentration gradient

Question 11

Na+/K+ ATPase (active transporter)

Answer 11

Antiport: 3 Na+ out of the cell for every 2 K+ into the cell

Direct active transport: Energy from ATP hydrolysis

Question 12

Na+/glucose Symporter (active transport)

Answer 12

Symport: Na+ and glucose into the cell

Indirect active transport: energy from diffusion on Na+ down its concentration gradient used to transport glucose up its concentration gradient