LEAVES

• what are the stomata the site of

  gas exchange
• what opens and closes the stomata

  guard cells
• what are palisade mesophyll the site of

  photosynthesis
• what is the purpose of spongy mesophyll

  helps maintain carbon dioxide concentration gradient by providing air spaces which allows carbon dioxide to rapidly diffuse into cells
• what enters and leaves the stomata

  carbon dioxide enters and oxygen leaves
• why does oxygen diffuse out of the leaf


  because it is produced in respiration meaning there's a higher concentration of oxygen inside the leaf than in atmosphere
• how is the stomata adapted to reduce water loss

  guard cells shrink at night causing the stomata to shut as there is less/no light and no photosynthesis will take place
• what are xerophytic plants


  plants that are adapted to survive in environments with limited water
• why do xerophytic plants try to trap evaporated water

  as it increases internal humidity of plant which increases internal water potential meaning water doesn't diffuse out of plant via osmosis
• what are three xerophyte adaptations which increase local humidity

  1. curled leaves to trap moisture
  2. hairs to trap moisture
  3. sunken stomata to trap moisture
• how do xerophytes reduce evaporation

  by having a thicker cuticle
• how do xerophytes gain access to more water

  having a longer root network