Membrane Transport and Diffusion Concepts

The video tutorial covers types of questions on the AP exam, focusing on diffusion and osmosis concepts. It explains a dialysis tubing experiment, predicting diffusion rates based on concentration gradients. The tutorial also discusses water potential in potato cells, highlighting equilibrium and pressure potential. Finally, it describes how membrane protein channels and pumps contribute to selective permeability, contrasting with semi-permeable membranes.

What type of questions are typically found at the end of the AP exam?

• Essay questions

• True or false questions

• Short answer questions

• Multiple choice questions

In the diffusion experiment, what is the concentration gradient when using 5% sodium chloride solution in distilled water?

• 0% to 5%

• 5% to 0%

• 5% to 5%

• 0% to 0%

If the diffusion rate with 5% sodium chloride is 20 mg/L/s, what would it be with 1% sodium chloride?

• 5 mg/L/s

• 4 mg/L/s

• 2 mg/L/s

• 1 mg/L/s

What is the solute potential of the potato core in the experiment?

• 4 atmospheres

• 8 atmospheres

• 16 atmospheres

• 0 atmospheres

Why is the pressure potential considered zero in the potato core experiment?

• Because the beaker is open to the air

• Because the solute potential is zero

• Because the beaker is sealed

• Because the potato core is impermeable

At what point will water stop moving into the potato cells?

• When the pressure potential inside equals the outside

• When the solute potential inside equals the outside

• When the solute potential inside is zero

• When the water potential inside equals the outside

How do membrane protein channels contribute to selective permeability?

• By allowing all substances to pass through

• By using energy to open and close

• By being impermeable to all substances

• By having fixed openings

What is the main difference between a selectively permeable membrane and a semi-permeable membrane?

• Selectively permeable membranes can control what enters and exits

• Semi-permeable membranes use energy to transport substances

• Semi-permeable membranes are impermeable to all substances

• Selectively permeable membranes allow all substances to pass

What role does ATP play in membrane pumps?

• It creates openings in the membrane

• It blocks substances from entering

• It provides energy for transport

• It acts as a barrier

What happens when a membrane pump does not use ATP?

• Substances are blocked

• Substances do not move

• Substances move freely

• Substances move against the gradient