Type A Multiple Choice: ONE out of the five possible choices is correct.
1. A glucose transporter (facilitated diffusion), GLUT‐1, is transporting glucose into a cell at its transport
maximum (T m). The cell is then transferred into a solution of higher glucose concentration. What would
happen to the amount of glucose entering the cell? Assume glucose is too larger and hydrophilic to
diffuse in, significantly.
a) It increases, as long as concentration increases, transport will increase.
b) It remains the same, the transporter is functioning at its maximum rate.
c) It decreases, the transporter will be overwhelmed.
d) It decreases, an increase in the concentration will lead to a decrease in the transport
e) It depends, if there is enough ATP the transporter will be able to accommodate the increase.
2. Which of the following statements about the Na /K ATPase and its postulated mechanism of function
is NOT correct?
a) Typically transports 3 sodium ions out of the cell.
b) Is phosphorylated during its transport cycle.
c) Typically transports 2 potassium ions into the cell.
d) Is an example of secondary active transport.
e) Is a significant source of energy expenditure for most cells.
3. A cell recently taken from a polar bear is introduced into a solution of 200 milliosmolar (mOsm)
potassium and 200 mOsm chloride. What happens in the long run, considering that potassium and
chloride channels do not contribute significantly to movement of the solutes in this cell?
a) Solution is hypertonic and hyperosmotic, the cell will shrink.
b) Solution is hyperosmotic but isotonic, the cell will not change in size.
c) Solution is isoosmotic but hypertonic, the cell will shrink.
d) Solution is isoosmotic and isotonic, the cell will not change in size.
e) Solution is hypoosmotic and hypotonic, the cell will enlarge and maybe burst. 4. A cell recently taken from a polar bear is introduced into a solution