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Diffusion

Biology • Cell Membrane & Transport • Knowledge-Based • 5 questions

Diffusion Knowledge-Based Download PDF

Biology · Cell Structure & Function · Biology · Cell Membrane & Transport

5 Biology practice questions on Diffusion. Questions that assess core concepts and understanding.

Questions

  1. 1.

    What is the direct source of energy that drives the passive diffusion of solute molecules across a cell membrane?

    • A) Chemical energy released from the hydrolysis of intracellular ATP
    • B) Thermal kinetic energy causing continuous, random motion of the molecules
    • C) Proton-motive force established by active electron transport chains
    • D) Cytoskeletal tension exerted by microfilaments anchored to the membrane
  2. 2.

    Which of the following substances crosses the cell membrane primarily by simple diffusion directly through the phospholipid bilayer without the assistance of transport proteins?

    • A) Carbon dioxide
    • B) Glucose
    • C) Sodium ion
    • D) Sucrose
  3. 3.

    Which of the following changes would decrease the net rate of diffusion of a substance across a cell membrane?

    • A) An increase in the thickness of the membrane
    • B) An increase in the temperature of the solution
    • C) An increase in the surface area of the membrane
    • D) An increase in the magnitude of the concentration gradient
  4. 4.

    What occurs when a diffusible substance reaches dynamic equilibrium across a cell membrane?

    • A) Individual molecules continue to cross the membrane in both directions at equal rates, resulting in no net change in concentration.
    • B) All molecular motion stops completely once concentrations on both sides of the membrane become equal.
    • C) Molecules are actively pumped across the membrane in one direction to prevent further diffusion.
    • D) The membrane becomes completely impermeable to the solute to stabilize the intracellular environment.
  5. 5.

    Which of the following statements correctly describes the process of simple diffusion across a biological membrane?

    • A) It is the passive net movement of solute molecules down their concentration gradient without requiring cellular energy expenditure.
    • B) It requires the hydrolysis of ATP to transport solute particles against their concentration gradient.
    • C) It relies exclusively on specialized membrane pumps to move polar substances into areas of greater concentration.
    • D) It involves the active movement of large macromolecules through the lipid bilayer until an unequal distribution is maintained.