Chapter 41 - Animal Renal Systems

Question 1

What is homeostasis?

Answer 1

The maintenance of a stable internal environment in the face of changing external environment and as result of molecules produced by normal physiological activity

Question 2

What is osmosis and what gradient does it consider?

Answer 2

It is the net movement of water molecules from higher water concentration to regions of lower water concentration, or the movement of water from regions of lower solute concentration to higher solute concentration.

Question 3

What are the properties of cell membranes?

Answer 3

They are semipermeable/selectively permeable because of the combination of lipid bilayer and transmembrane proteins

Question 4

How does water move through the plasma membrane?

Answer 4

By free diffusion or by channels call aquaporins via facilitated diffusion.

Question 5

What is osmotic pressure?

Answer 5

The tendency of water to move from one solution into another by osmosis, and it drives the movement of water. There is a higher tendency for water to move from areas of low solute to high solute concentration.

Question 6

At what point does osmosis stop? Can water molecules still diffuse across the membrane?

Answer 6

When the water’s osmotic pressure equals hydrostatic pressure and equilibrium is reached.
Water molecules are stilla ble to move across the membrane in both directions by diffusion but no net movement of water molecules.