A) Depolarization C) Blood-brain barrier
B) Potassium spatial buffering D) Goldman equation
12. Distinguish between the “head” and “tail” of phospholipids. Choose the correct option.
A) The phospholipids have a nonpolar “head” and polar “tail.”
B) The phospholipids “head” contains hydrophilic phosphate and “tail” contains a hydrophobic hydrocarbon.
C) The phospholipid “head” is hydrophobic and the hydrocarbon “tail” is hydrophilic.
D) The phospholipid “heads” face each other and “tails” face the watery extracellular and intracellular environments.
13. In which condition do astrocytes take up extracellular K+? Choose the correct option.
A) Rise in extracellular potassium concentrations
B) Fall in extracellular potassium concentrations
C) Potassium equilibrium potential
D) All of the above
14. Which of the following factors determines the ion selectivity of specific ion channels? Choose the correct option.
A) Number of protein molecules assembling to form a pore
B) Number of ion channels in the membrane
C) Nature of the R groups lining the ion channel
D) Gating properties
15. Two types of cells have excitable membranes, neurons and muscle cells.
16. Protein shape influences protein function.
17. Peptide bonds are a single chain of amino acids.
18. The differences between amino acids result from the differences in the size and nature of the R groups.
19. The subunits of different potassium channels have common structural features that bestow selectivity for K+ ions. ______________ is one such structural feature.
Ans: Pore loop
20. All amino acids have a central _________ atom.
Ans: Alpha carbon