cell transport

• what is diffusion?

  The net movement of particles from an area of high concentration to an area of low concentration
• what three factors affect the rate of diffusion?

  Concentration gradient temperature and the membrane surface area
• how are villi adapted for exchanging substances?

  Long and thin - increase the surface area

  One cell thick membrane - short diffusion pathway

  Good blood supply- maintains a steep concentration gradient
• how are the lungs adapted for a efficiant gas exchange?

  alveoli - large surfarce are

  Moist membranes - increases rate of diffusion

  One Cell thick membranes - short diffusion pathway

  Good blood supply- maintains a steep concentration gradient
• how a fish gills adapted for efficient gas exchange

  Large surface area for gases to diffuser across

  Thin layer of cells - short diffusion pathway

  Good blood supply- maintains a steep concentration gradient
• what is osmosis?

  Diffusion of water from a dilute solution to a concentration solution through a partially permable membrane
• give one example of osmosis in a plant

  Water moves from the soil into the root hair cell
• what is active transport?

  The movement of particles against a concentration gradient from a dilute solution to a more concentration solution using energy
• why is active transport needed im plant roots?

  Concentration of minerals irons in soil is lower than inside the real hair cells. The minimal irons must move against the concentration gradient to enter the root hair cells
• what is the purpose of active transporting in the small intestine?

  Sugar can be absorbed when the concentration of sugar in this morning testing is lower than the concentration of sugar in the blood