Question

Na' Key Na transport channel Figure A Figure B For the figures above, the inner circle represents a cell which is surrounded by a solution. For the purposes of these questions, assume each molecule of Nat 1 M and each molecule of Ca2+ 2M. Assume each molecule of H2O represents 100 mL. Hint: Don't overthink these! I) Figure A: Suppose the cell pictured is at its normal volume and has a semipermeable membrane. Which of the 3 molecules in the figure can cross the membrane? B) What is the osmolarity of: The cell? The solution? C) Will the volume of the cell change? If so, by how much/how little? D) ls the surrounding solution hypertonic, isotonic, or hypotonic? 11) Figure B: Suppose the cell pictured is at its normal volume and has a selectively permeable membrane. A) This membrane is permeable to water. Which of the 2 substrates in the figure can also cross the membrane? B) Following crossing, how many particles of each substrate will be present in the cell? In the solution? IIl. One general principle states that physiological processes are dictated by the laws of chemistry and physics. How does this relate to the movement of molecules through either the lipid bilayer membrane alone or with membrane proteins (and provide an example of each)

Answer 1

ANSWER :

1). (A) Semipermeable membrane allows specific type of diffusion called osmosis. In the figure one more solutes present inside cell hence, only water (H2O) molecules moves from membrane.

1.(B) The osmolarity of cell is higher than outside solution due presence more ionic concentration of Ca++ and Na+ in cytoplasm.

1.(C) The cell would swell little due to endosmosis of H2O molecules toward cytoplasm.

1.(D) The solution of cell is hypertonic with respected to outside solution due to more solute concentration of calcium and sodium.