* not completed

. Gases such as oxygen and carbon dioxide cross the plasma membrane by which of the following processes:

secondary active transport correct incorrect

passive diffusion through the lipid bilayer correct incorrect

specific gas transport proteins correct incorrect

primary active transport correct incorrect

* not completed

. A substance only can be accumulated against its electrochemical gradient by which of the following processes:

facilitated diffusion correct incorrect

Passage through ion channels correct incorrect

Diffusion through a uniport correct incorrect

Active transport correct incorrect

* not completed

. Which of the following is the principal intracellular cation?

Na⁺ correct incorrect

Cl^- correct incorrect

K⁺ correct incorrect

Ca²⁺ correct incorrect

* not completed

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

Cl--HCO_3- exchange correct incorrect

Na⁺ - H⁺ exchange correct incorrect

Na⁺-Ca²⁺ exchange correct incorrect

The Na⁺, K⁺ ATPase correct incorrect

* not completed

. Which of the following statements concerning the sodium pump is correct? Please select all that apply

It exchanges extracellular Na⁺ for intracellular K⁺ correct incorrect

It is important for maintaining a constant cell volume correct incorrect

It can be inhibited by metabolic poisons such as cyanide correct incorrect

Is an ion channel correct incorrect

* not completed

. The resting membrane potential of a mammalian cell is:

-20 mV correct incorrect

mainly determined by the K⁺ gradient correct incorrect

mainly determined by the Cl^- gradient correct incorrect

mainly determined by the Na⁺ gradient correct incorrect

* not completed

. Which of the following statements about exocytosis is correct? Please select all that apply

Is employed by cells for the secretion of polar molecules correct incorrect

Is used to deliver material into the extracellular space correct incorrect

Takes up large molecules from the extracellular space correct incorrect

Allows the retrieval of elements of the plasma membrane correct incorrect

* not completed

. Endocytosis is used by cells to:

Ingest bacteria and cell debris correct incorrect

Retrieve elements of the plasma membrane after exocytosis correct incorrect

Secrete�large molecules into the extracellular space correct incorrect

* not completed

. Intracellular hydrogen ions are passively distributed across the cell membrane

True correct incorrect

False correct incorrect

* not completed

. Water moves across the cell membrane via the lipid bilayer

True correct incorrect

False correct incorrect

* not completed

. Which of the following values is closest to equilibrium potential of potassium when the intracellular and extracellular concentrations are 4 and 150 mmol l^- and the temperature is 37 C:

-20 mV correct incorrect

-100 mV correct incorrect

+100 mV correct incorrect

-50 mV correct incorrect

* not completed

.

The ionic composition (mmol l^-) of skeletal muscle is as follows:

Use the Nernst equation to calculate the equilibrium potential and  RT/F =26.7 mV at 37°C. Which of the statements listed below are correct?

The equilibrium potential for Na⁺ is +53 mV. correct incorrect

The equilibrium potential for Ca²⁺ is +40 mV. correct incorrect

The equilibrium potential for Cl^- is -97 mV. correct incorrect

The equilibrium potential for K⁺ is -70 mV. correct incorrect

* not completed

. When the membrane potential is negative with a value of about -70 mV the permeability of the membrane to Na⁺ is much less than its permeability to K⁺.

True correct incorrect

False correct incorrect