MCB 2000 Lecture Notes - Lecture 6: Endospore, Facilitated Diffusion, Osmotic Pressure

Read the following scenarios and indicate which of the following processes they describe.

11. Sodium molecules move randomly around a solution of sodium chloride in water, frequently colliding with other sodium ions and chloride ions. secondary active transport diffusion osmosis facilitated diffusion primary active transport

12. Sodium ions (Na+) move through sodium channels in a synthetic membrane. primary active transport secondary active transport facilitated diffusion osmosis

13. Water molecules move into the cytosol of a cell placed in a hypotonic solution. primary active transport secondary active transport facilitated diffusion osmosis

14. Water molecules move into the cytosol of a cell placed in pure water. facilitated diffusion osmosis secondary active transport primary active transport

15. Water molecules move out of a cell placed in a hypertonic solution. facilitated diffusion primary active transport secondary active transport osmosis

16. The action of sodium-potassium pumps moves sodium ions (Na+) out of a cell and potassium ions (K+) into a cell. facilitated diffusion secondary active transport osmosis primary active transport

17. Glucose molecules move into cells lining the intestine against their concentration gradient driven by the movement of sodium ions (Na+) into the cells down their concentration gradient. osmosis secondary active transport primary active transport facilitated diffusion

18. A beaker of water is separated by a selectively permeable membrane that allows the passage of water but not ions. A solution of 4% sodium chloride (NaCl) is placed on one side of the membrane and pure water is placed on the other side of the membrane. The solutions are allowed to equilibrate. At this point, which process is going on? facilitated diffusion osmosis secondary active transport primary active transport

Which is the only substance involved in osmosis?

alcohol

salt

sugar

water

If a solution outside of a cell has a lower concentration of solutes inside of a cell, it is referred to as what?

hypotonic

facilitated

hypertonic

isotonic

In an electron microscope, what type of cells are used?

dead, but fresh cells

live and fresh cells

dead, processed cells

live, processed cells

Which model best describes the observations and functions of the plasma membrane?

phospholipid bilayer

cell membrane

fluid mosaic model

nuclear envelope

1. predict the direction of water movement based on differences in solute concentrations. Use the terms osmotic pressure, hypotonic, isotonic, and hypertonic
2. Why do membranes have to be selectively permeable?

3. What determines whether a particular substance can diffuse (simple or facilitated) through a membrane?

4. What mechanisms drive molecules across membranes? Use the terms concentration gradient, (facilitated) diffusion and active transport.
5. Which parts of the plasma membrane proteins do you expect to be hydrophobic or hydrophilic? Justify your answer.
concise and short answers pls