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d FiltrMembrane Transport: Diffusion, Osmosis, anation lab 6

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Termini in questo insieme (21)

  • Define solute, solvent, and solution.

    Solute is the substance dissolved in a solvent. Solvent is the fluid that dissolves the solute. A solution is a homogeneous mixture of solute dissolved in solvent.

  • What is a concentration gradient?

    A concentration gradient is the difference in solute concentration between two regions, driving diffusion from high to low concentration.

  • What is diffusion?

    Diffusion is the passive movement of particles from regions of high concentration to low concentration until equilibrium is reached.

  • List factors that affect the rate of diffusion.

    Rate of diffusion increases with higher concentration gradient, higher temperature, smaller molecular weight, and larger membrane surface area and permeability.

  • What is osmosis?

    Osmosis is the movement of water across a selectively permeable membrane from higher water concentration (lower solute) to lower water concentration (higher solute).

  • What is a selectively permeable membrane?

    A membrane that allows some molecules (like water, oxygen) to pass but blocks others (like proteins and ions).

  • Explain osmotic pressure.

    Osmotic pressure is the pressure required to stop water movement across a membrane due to osmosis, proportional to the osmotic potential (solute concentration difference).

  • Define hypertonic, hypotonic, and isotonic solutions.

    Hypertonic: higher solute concentration; Hypotonic: lower solute concentration; Isotonic: equal solute concentration compared to another solution.

  • How does water move between hypertonic and hypotonic solutions?

    Water moves from the hypotonic (lower solute) solution to the hypertonic (higher solute) solution until equilibrium is reached.

  • What is filtration in biological systems?

    Filtration is the process where hydrostatic pressure forces fluid and small particles through a membrane, leaving larger particles behind.

  • Give an example of filtration in the human body.

    Filtration occurs in the kidneys where blood pressure forces small molecules like urea and ions through membranes into kidney tubules, while proteins remain in blood.

  • How does cell size affect diffusion efficiency?

    Smaller cells have a higher surface area to volume ratio, allowing more efficient diffusion of substances across the membrane.

  • Why do smaller molecules diffuse faster than larger ones?

    Smaller molecules have less mass and move more rapidly, increasing their rate of diffusion compared to larger molecules.

  • What role do aquaporins play in osmosis?

    Aquaporins are channel proteins that facilitate faster water movement across the plasma membrane during osmosis.

  • Describe the effect of membrane permeability on diffusion rate.

    Higher membrane permeability (larger pores or more channels) increases the rate at which molecules diffuse across the membrane.

  • What happens to a cell placed in a hypertonic solution?

    Water moves out of the cell into the hypertonic solution, causing the cell to shrink (crenate).

  • What happens to a cell placed in a hypotonic solution?

    Water moves into the cell from the hypotonic solution, causing the cell to swell and possibly burst (lyse).

  • What is equilibrium in diffusion and osmosis?

    Equilibrium is reached when solute concentrations are equal on both sides of the membrane and net movement of particles or water stops.

  • How does temperature affect diffusion?

    Higher temperature increases particle kinetic energy, speeding up the rate of diffusion.

  • Explain the difference between passive and active transport.

    Passive transport requires no energy and moves substances down their concentration gradient; active transport requires ATP to move substances against their gradient.

  • What is the significance of the surface area to volume ratio in cells?

    A higher surface area to volume ratio allows more efficient exchange of materials across the cell membrane relative to cell volume.