Transport in Cells

• What is diffusion?

  The spreading out of particles
• How do particles move during diffusion?

  From higher concentration to lower concentration
• Which molecules can diffuse through cell membranes?

  Very small molecules like oxygen and glucose
• What is osmosis?

  The movement of water molecules
• In which direction do water molecules move during osmosis?

  From higher water concentration to lower water concentration
• What factors increase the rate of diffusion across a cell membrane?

  • A high concentration gradient
  • A high temperature
  • A large surface area
• What is active transport?

  The movement of a substance against the concentration gradient
• What does active transport require that diffusion does not?

  Energy from respiration
• Why is active transport important for plants?

  It allows mineral ions to be absorbed from soil
• How does glucose enter the bloodstream?

  Through active transport from the gut
• What are the differences between diffusion, osmosis, and active transport?

  • Diffusion: Movement from high to low concentration, no energy required
  • Osmosis: Movement of water from high to low water concentration, no energy required
  • Active Transport: Movement against concentration gradient, requires energy