transport in cells

• What are the main factors effecting the rate of diffusion?


  • Larger concentration gradient
  • Higher temperature
  • Larger surface area
• What is diffusion?


  The movement of particles from an area of higher concentration to an area of lower concentration.
• What is an examples of diffusion in the lungs?


  • Oxygen diffused into the blood from the lungs.
  • Carbon dioxide diffused into the lungs from the blood
• What are examples of diffusion in the kidney?


  • urea diffused from the cells into blood plasma so it can be excreted in urine.
• How are single-celled organisms adapted from diffusion?


  They have a large surface area to volume ratio and this maximises the rate of diffusion of molecules.
• What is osmosis?


  The movement of water from a dilute solution to a concentrated solution through a partially permeable membrane.
• What is active transport?


  The movement of water molecules from a more dilute to a more concentrated solution against a concentration gradient - using energy from respiration.
• How do plant root cells use active transport?


  They use active transport to take up mineral ions from a more dilute solution in soils.
• How is active transport used to absorb the products of digestion?


  It is used to transport glucose from lower concentration into the gut to a higher concentration in the blood. Then it is transported into the tissues and used in respiration.