1. Considering the movement of molecules across the plasma membrane:
a. Contrast the manner in which alcohol and water enter a cell.Answer
b. Contrast the manner in which sodium ions (Na+) and chloride ions (Cl-) exit a cell.Answer
c. Contrast the manner in which amino acids and proteins enter a cell.Answer
d. How might the proteins from question c be digested?Answer
2. Exocytotic vesicles add plasma membrane to the cell, and endocytotic vesicles remove plasma membrane.
a. In a cell in which the amount of plasma membrane stays constant, how many exocytotic vesicles per endocytotic vesicles would you expect?Answer
b. Imagine a cell that is moving from left to right. If vesicle formation is facilitating movement, where would you expect exocytosis to be occurring? Where would you expect endocytosis to be occurring?Answer
c. Receptor-mediated endocytosis is a process by which a substance combines with a receptor before endocytosis brings the entire complex into the cell. Imagine a virus that enters a cell in this manner. If so, what additional step is needed for the virus to enter the cell proper?Answer
