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Diffusion and Osmosis in General Biology(Lab5Slide)

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Termini in questo insieme (20)

  • What is diffusion?

    Diffusion is the spontaneous movement of solutes down their concentration gradient from an area of higher concentration to an area of lower concentration.

  • What types of molecules can freely diffuse through the plasma membrane?

    Small non-polar molecules such as hydrocarbons, CO2, and O2 can move freely through the hydrophobic center of the phospholipid membrane.

  • What is selective permeability of the plasma membrane?

    Selective permeability means the plasma membrane allows some solutes to pass while blocking others, controlling movement into and out of the cell.

  • What is passive transport?

    Passive transport is the movement of solutes across a membrane without energy expenditure, occurring with or without protein assistance.

  • What is facilitated diffusion?

    Facilitated diffusion uses protein channels to allow ions and small polar molecules to cross the membrane down their concentration gradient without energy.

  • What is active transport?

    Active transport requires energy to move solutes against their concentration gradient from lower to higher concentration.

  • What is osmosis?

    Osmosis is the facilitated diffusion of water molecules across a selectively permeable membrane through aquaporin channels.

  • Define hypertonic, hypotonic, and isotonic solutions.

    A hypertonic solution has higher solute concentration, hypotonic has lower solute concentration, and isotonic solutions have equal solute concentrations.

  • What is osmolarity?

    Osmolarity is the relative concentration of solutes in a solution compared to another.

  • How does water move during osmosis?

    Water moves from the hypotonic side (lower solute concentration) to the hypertonic side (higher solute concentration) to equilibrate solute concentrations.

  • What is osmotic pressure?

    Osmotic pressure is the pressure exerted on the cell membrane by the flow of water during osmosis.

  • What happens to a cell in a hypertonic solution?

    Water moves out of the cell causing it to shrink or plasmolyze due to higher external solute concentration.

  • What happens to a cell in a hypotonic solution?

    Water moves into the cell causing it to swell or become turgid due to lower external solute concentration.

  • What happens to a cell in an isotonic solution?

    Water moves equally in and out, so the cell remains flaccid with no net change in volume.

  • What is osmoregulation?

    Osmoregulation is the control of water balance in organisms to prevent cell damage from excess swelling or shrinking.

  • Give an example of osmoregulation in unicellular organisms.

    Contractile vacuoles in freshwater protists pump out excess water to maintain osmotic balance.

  • Give an example of osmoregulation in humans.

    Kidneys regulate water balance by removing excess water from the body.

  • Why can't ions and polar molecules freely diffuse through the plasma membrane?

    Because the hydrophobic center of the phospholipid bilayer repels charged and polar molecules, requiring protein channels for transport.

  • What role do protein channels play in membrane transport?

    Protein channels facilitate the selective movement of ions and polar molecules across the membrane without energy use.

  • How does active transport differ from passive transport in terms of energy and direction?

    Active transport uses energy to move solutes against their concentration gradient, while passive transport moves solutes down the gradient without energy.