Diffusion, active transport and osmosis

• What are two ways substances can move in and out of cells?

  Diffusion and active transport
• What is diffusion?

  Diffusion is the net movement of particles from higher concentration to lower concentration.
• In which states of matter does diffusion occur?

  Diffusion occurs in both liquids and gases.
• What is the role of cell membranes?

  Cell membranes hold the cell together and allow substances to move in and out.
• What types of molecules can diffuse through cell membranes?

  Very small molecules like glucose, amino acids, water, and oxygen can diffuse through cell membranes.
• What is active transport?

  Active transport is the movement of particles against a concentration gradient using ATP.
• How does active transport work in the digestive system?

  Active transport allows nutrients to be absorbed into the blood from the gut against the concentration gradient.
• What is osmosis?

  Osmosis is the net movement of water molecules across a partially permeable membrane from higher water concentration to lower water concentration.
• What is a partially permeable membrane?

  A partially permeable membrane has very small holes that allow only tiny molecules to pass through.
• What happens to water molecules during osmosis?

  Water molecules move randomly and pass both ways through the membrane during osmosis.
• What is water potential?

  Water potential is the likelihood of water molecules to diffuse out of or into a solution.
• How does turgor pressure support plant cells?

  Turgor pressure is created when water enters plant cells, making them plump and swollen, which supports plant tissues.
• What happens to a plant when there is no water in the soil?

  The plant starts to wilt as its cells become flaccid and lose water.
• Why can animal cells burst in a solution with a higher water potential?

  Animal cells can burst because they lack cell walls and can take in too much water.