Osmosis is the diffusion of water, and can be driven by many different factors, including temperature, pressure, the nature of the location, and solute concentration. Which of these is a requirement for osmosis to occur?     Water must flow from low to high water potential.   Only within plant cells is pressure required.   Temperature must be above 30 C.   There must be a semipermeable membrane.

Concentration of Water and Solutes in Four Adjacent Cells Water: low Solutes: low 3 Water: high Solutes: low cell 1 1— cell 2 cell 3 cell 4 D D n JP. A 1 Refer to the illustration above. Which cell is most likely to lose both water molecules and solute molecules as the system approaches equilibrium? U 2 Water: low Solutes: high 4 Water: high Solutes: high

1) Draw a model of the plasma membrane to form a cell.  Include a tube embedded in the membrane.  Show 2 water molecules inside the cell and 12 water molecules outside the cell.  Indicate which way the water will move through the aquaporin with an arrow. a) Using your knowledge of membrane transport, which direction will the water molecules move through the aquaporin? Why? b) Why would water have a difficult time crossing the cell membrane? Keep in mind the structure of water in your answer.  2) Develop an explanation for the necessity of having kinks in the hydrophobic tail of the phospholipids that make up cell membranes. a) Develop an explanation for the necessity of having kinks in the hydrophobic tail of the phospholipids that make up cell membranes.

Explain how osmosis works including the concept of concentration gradient