Define the terms hypotonic, hypertonic, and isotonic and discuss ...

[tingc95]

Define the terms hypotonic, hypertonic, and isotonic and discuss their relationship to osmotic pressure.
 
  What will be an ideal response?

Question 2

Judge the following sentence according to the criteria given below: Baleen whales are generally much larger than toothed whales BECAUSE they eat lower on the food web.
 
  A) The assertion and the reason are both correct, and the reason is valid.
  B) The assertion and the reason are both correct, but the reason is invalid.
  C) The assertion is correct, but the reason is incorrect.
  D) The assertion is incorrect, but the reason is correct.
  E) Both the assertion and the reason are incorrect.

[mrphibs]

Answer to Question 1

When water solutions of unequal salinity are separated by a semipermeable membrane (such as skin or the membrane around a living cell), water molecules (but not dissolved ions) diffuse through the membrane. To equalize the salt concentration on both sides of the membrane, water molecules always move from the less concentrated solution into the more concentrated solution in a process called osmosis. Osmosis is diffusion that produces a net transfer of water molecules through a semipermeable membrane from the side with the greatest concentration of water molecules to the side with the lesser concentration of water molecules. An organism is hypotonic relative to the water outside its body if the salinity within an organism's cells is less than that of the surrounding seawater, water from the cells will pass through the cell membranes out into the seawater (toward the more concentrated solution). An organism is hypertonic if seawater has a lower salinity than the fluid within an organism's cells; seawater will pass through the cell walls into the cells (always toward the more concentrated solution). If the salinity of an organism's body fluid equals that of the ocean, it is isotonic and has equal osmotic pressure, and so no net transfer of water will occur through the membrane in either direction.

Answer to Question 2

A