Biological Membranes A-level OCR

Which one of the following is not a major component of the cell surface membrane?

• glycolipid

• glycoprotein

• cholesterol

• triglyceride

If two sucrose solutions of different concentrations are separated by a partially permeable membrane, which one of the following will occur?

• The solute will diffuse from the more concentrated to the less concentrated solution.

• Both solute and solvent will diffuse until equilibrium is reached.

• The volume of the less concentrated solution will increase.

• The volume of the less concentrated solution will decrease.

What is the approximate thickness of the plasma membrane?

• 0.75 nm

• 7.5 nm

• 75 nm

• 750 nm

The diagram shows a glass cylinder separated into two compartments, T and S, by a partially permeable membrane. The membrane is in the form of a sliding piston.

· the volume of T equals the volume of S (V_T = V_S).

· the concentration of sucrose solution in T is twice that in S (C_T = 2C_S).

Which one of the following will be true when osmotic equilibrium is reached?

• C_T = 2C_S and V_T = 2V_S

• C_T = C_S and V_T = V_S

• C_T = 2C_S and V_T = V_S

• C_T = C_S and V_T = 2V_S

Potassium cyanide interferes with the formation of ATP. The use of potassium cyanide reduces the rate at which molecules of a certain chemical enter the cell.

Select the process by which the molecules would normally enter the cell.

• simple diffusion

• facilitated diffusion

• osmosis

• active transport

If four solutions are made, each containing 10 g l ^-1 of one of the following molecules, which one would have the lowest water potential?

• sucrose

• glucose

• DNA

• haemoglobin

The vacuolar sap of a freshwater alga Nitella clavata and the pond water in which it was growing were analysed. The table shows the results.

Which one of the following processes accounts for these results?

• active transport

• facilitated diffusion

• osmosis

• simple diffusion

Which one of the following is not an acceptable description of the permeability of a cell surface membrane?

• differentially

• partially

• selectively

• semi

Which of these has the highest water potential?

• 5% sucrose solution

• 10% sucrose solution

• 20% sucrose solution

• pure water

Which diagram shows the appearance of a plant cell with an original ψ of -1.2 MPa after being placed in a solution as shown?

• A

• B

• C

• D