plant structures and their functions

• photosynthetic producers are the main producers of what?

  food (biomass)
• what type of reaction is photosynthesis?

  endothermic
• what is the equation for photosynthesis?

  carbon dioxide + water → glucose + oxygen
• what are the factors that affect photosynthesis?

  • temperature
  • light intensity
  • carbon dioxide concentration
• how does temperature limit the rate of photosynthesis?

  • At low temperatures photosynthesis is limited by the number of collisions between enzymes and substrates.
  • At high temperatures enzymes become denatured or damaged which decreases rate of photosynthesis
• what does the square inverse law state?

  The rate of photosynthesis is directly proportional to light intensity and inversely proportional to the distance from the light source.
• how is the root hair cell adapted to absorb water and mineral ions?

  • large surface area
• what does the xylem do?

  transport water ad nutrients from the soil to the leaves
• what does the phloem do?

  transports glucose and amino acids throughout the plant
• how is the phloem adapted to its function?

  • living cells
  • sieve tubes
  • end to end cells
• how is the xylem adapted to its function?

  • dead cells
  • continuous tube
  • lignin
• what is transpiration?

  when water evaporates from the plant into the atmosphere
• what is translocation?

  transporting dissolved substances such as amino acids and sugars within a plant through the phloem
• how are mineral ions and water transported through the plant?

  xylem
• how are amino acids and glucose transported through the plant?

  phloem
• where is the stomata found?

  in the lower epidermis of the leaf, surrounding by a pair of guard cells
• what is the function of the stomata?

  controls gas exchange and water loss by opening an closing
• how is the structure if the leaf adapted for photosynthesis sand gas exchange?

  • large surface area
  • thin structure
  • stomata
  • air spaces
• how does temperature effect the water uptake by a plant?

  as temperature increases, water molecules move faster causing evaporation to occur more quickly. This increases rate of transpiration.
• how does light intensity affect water uptake by a plant?

  higher the rate of light intensity, increase in rate of photosynthesis which increases the plants demand for water. Light also stimulates the stomata to open which speeds up transpiration
• how does air movement affect water uptake by a plant?

  air movement increases the rate of water uptake by a plant because it move the layers of water vapour surrounding the leaf
• how can the rate of transpiration be calculated?

  • potometer
• what do auxins do?

  control plant growth and change rate of elogongation
• what do gibberellins do?

  promote plant growth and development
• what does ethene do?

  controls plant growth and ripening and causes leave to drop
• what is phototropism?

  the ability for plants to bend grow towards the light
• what is gravatropism?

  A plants response to gravity which causes the roots to grow down and the shoots to grow up.
• what are some commercial uses for auxins?

  • weedkillers
  • rooting powders
• what are some commercial uses for gibberellin?

  • germination
  • fruit and flower formation
  • production of seedless fruit
• what is the commercial use for ethene?

  • fruit ripening