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Question 01

Gases such as oxygen and carbon dioxide cross the plasma membrane by:

a) secondary active transport.

b) passive diffusion through the lipid bilayer.

c) a specific gas transport proteins.

d) primary active transport.

Question 02

A substance only can be accumulated against its electrochemical gradient by:

a) facilitated diffusion.

b) passage through ion channels.

c) diffusion through a uniport.

d) active transport.

Question 03

The principal intracellular cation is:

a) Na⁺

b) Cl^-

c) K⁺

d) Ca²⁺

Question 04

Which of the following is an example of primary active transport?

a) Cl^--HCO₃^- exchange

b) Na⁺ - H⁺ exchange

c) Na⁺-Ca²⁺ exchange

d) The Na⁺, K⁺ ATPase

Question 05

The sodium pump:

a) exchanges extracellular Na⁺ for intracellular K⁺.

b) is important for maintaining a constant cell volume.

c) can only be inhibited by metabolic poisons.

d) is an ion channel.

Question 06

The resting membrane potential of a mammalian cell is:

a) -20 mV.

b) is mainly determined by the K⁺ gradient.

c) is mainly determined by the Cl^- gradient.

d) is mainly determined by the Na⁺ gradient.

Question 07

Exocytosis:

a) is always employed by cells for secretion.

b) is used to deliver material into the extracellular space.

c) take up large molecules from the extracellular space.

d) allows the retrieval of elements of the plasma membrane.

Oxford University Press, Online Resource Centre, Chapter 04.

Chapter 04

Instructions