Cell Transport

• Diffusion 


  The spreading out of the particles of any substance in solution, or particles of a gas, causing a net movement from an area of higher concentration to an area of lower concentration
• Substances in Plant and animal transported in and out of cell by diffusion

  Oxygen, carbon dioxide, urea
• How does the difference in concentration affect the rate of diffusion

  Increased concentration gradient increase the rate of diffusion
• How does temperature affect rate of diffusion

  Increased temperature increases in the rate of diffusion because particles have more kinetic energy and are moving faster
• How does surface area of the membrane affect the rate of diffusion

  Increased surface area increases rate of diffusion
• How are single-cells organisms adapted for diffusion

  It has a large surface area to volume ratio
• How is the small intestine adapted for exchange

  It is long and has villi for a large surface area, the cell membranes are thin for short diffusion pathway, there is a rich blood supply to maintain a steep concentration gradient and lots of mitochondria
• How are lungs adapted for exchange

  Lots of alveoli for a large surface area, thin membrane for a short diffusion pathway and good ventilation and blood supply to maintain a steep concentration gradient.
• How are the gills in a fish adapted for exchange

  Large surface area, thin membrane for short diffusion pathway and good ventilation and blood supply to maintain a steep concentration gradient
• How are the roots adapted for exchange

  Large surface area, thin surface membrane for a short diffusion pathway and lots of mitochondria for active transport
• How are the leaves adapted for exchange

  Large surface area and thin for short diffusion pathway
• Osmosis

  The movement of water from a dilute to concentrated solution through a partially permeable membrane
• Active Transport 


  The movement of substances from a more dilute solution to a more concentrated solution (against the concentration gradient). It requires energy
• Example of active transport in animals 


  Absorption of sugar in the gut form a low to high concentration
• Example of active transport in plants


  Absorption of mineral ions into Plant root hairs