5. Cell Transport Across Plasma Membrane 2

Question 1

Electrical charges

Answer 1

Outside: charges of
Na+ ions are balanced by Cl- ions
Inside: charges of K+ ions are balanced by negative charges of organic molecules

Question 2

Ion channels

Answer 2

create openings for the passive movement of inorganic ions

Question 3

Gated ion-channels

Answer 3

Voltage-gated ion channels
Ligand-gated ion channels
Mechanically-gated ion channels

Question 4

Voltage-gated ion channels

Answer 4

controlled by changes in the voltage across the membrane

Question 5

Ligand-gated ion channels

Answer 5

controlled by
the binding of a molecule

Question 6

Mechanically-gated ion channels

Answer 6

controlled by a physical stimuli

Question 7

Depolarization

Answer 7

• Neuron stimulation shifts the membrane potential to a less negative value
• causes voltage-gated Na+ channels in the membrane to open transiently

Question 8

Action potentials

Answer 8

• result from rapid changes in voltage gated Na+ and K+ channels
• travel along axons
• jump along myelinated axons
• propagates in one direction