Active Transport

• What is the definition of active transport?

  Active transport is the movement of substances from a low to high concentration using energy.
• In which direction does active transport move substances?

  Active transport moves substances from a low to high concentration.
• What energy source is used for active transport?

  Active transport uses energy from respiration.
• What is passive transport?

  Passive transport does not require energy.
• What is an example of passive transport in plants?

  • Plant example: Root hair cell
  • Water particles move into the root hair cell
  • Water concentration is low in the root
• How does water enter the root hair cell?

  Water enters the root hair cell by diffusion through osmosis.
• What happens to water after it diffuses into the root hair cell?

  After diffusion, water is quickly moved upwards through the plant.
• What process pulls water upwards in plants?

  The process called transpiration pulls water upwards in plants.
• What happens to the concentration of water in the plant during transpiration?

  Transpiration creates a low concentration of water in the plant.
• What accumulates inside root hair cells?

  Mineral ions collect inside root hair cells.
• How do mineral ions enter root hair cells?

  Energy is used to pull mineral ions inwards from the soil.
• What is the structure of the cell membrane in root hair cells?

  • The cell membrane is studded with proteins.
  • Proteins act as pumps for active transport.
  • They collect minerals from lower concentration in the soil.
• Why is energy needed for the function of root hair cell proteins?

  Energy from respiration is needed for the proteins to actively transport minerals into the cell.
• What structures are found in the lining of the small intestine?

  • The lining contains villi.
  • Each villus is lined with a single layer of cells.
  • Villi have a good blood supply.
• What is the purpose of blood coming to each villus in the small intestine?

  The blood collects glucose and other food products to transport them to cells.
• What type of substances are present in the small intestine?

  The small intestine contains large insoluble food substances.
• How are large insoluble food substances processed in the small intestine?

  They are broken down by enzymes in the small intestine.
• How do broken down food substances enter the bloodstream?

  They move out through the single layer of cells in the villi into the bloodstream.
• What is diffusion in the context of the small intestine?

  Diffusion is the movement of molecules from high to low concentration.
• When does diffusion stop in the small intestine?

  Diffusion stops when there is an equal number of molecules on both sides.
• What is the structure of the villi in the small intestine?

  The villi are lined with a single layer of cells.