Photosynthesis

• How do plants make food??

  Photosynthesis
• Whats the word equation for photosynthesis?

  light

  Carbon dioxide +water ----------> glucose +oxygen
• Whats the symbol equation for photosynthesis?


  6CO2 + 6H2O → C6H12O6 + 6O2
• What reaction is photosynthesis?

  Endothermic reaction
• Whats an endothermic reaction?

  Energy is taken in
• What does photosynthesis require?


  Energy in the form of light
• How is light energy absorbed?

  Through a green pigment called chlorophyll
• Whats the main photosynthetic organ in plant?

  Leaves
• How does photosynthesis enter plant?

  Through stomata
• How does water enter plant?

  Through roots
• Where is water transported through, on way to leaves?

  xylem
• What is leftover glucose used for?

  Starch, lipids, amino acids and cellulose
• What are lipids in the plant used for?

  Storage in seed
• Whats cellulose used for?

  Build cell walls & add strength to cell walls
• What is starch used for?

  Its insoluable and storage form of carbohydrate
• Whats amino acids used for in plants?

  Absored from soil, amino acid molecules create protein
• How to measure photosynthesis rate?

  • the rate of oxygen output
  • the rate of carbon dioxide uptake
  • the rate of carbohydrate production
• What factors affect photosynthesis?

  • light intensity
  • carbon dioxide concentration
  • temperature
• Whats the description of limiting factor of light?

  At low light intensities, increase in photosynthesis rate is linear

  At this point, factor becomes limiting

  Graph levels off, rate becomes constant
• How is carbon dioxide limiting?

  If the concentration of carbon dioxide is increased, the rate of photosynthesis will therefore increase.

  Again, at some point, a factor may become limiting.
• How is temperature limiting?

  At low temperatures, the rate of photosynthesis is limited by the number of molecular collisions between enzymes and substrates. At high temperatures, enzymes are denatured.
• How is chlorophyll limiting?

  Leaves with more chlorophyll are better able to absorb the light required for photosynthesis.
• How to improve light intensity in plants?

  • use greenhouses constructed from glass or alternative materials that enable maximum transmission of light
  • position plants for maximum light absorption
• How to improve Carbon dioxide in plants?

  • use paraffin heaters on a small scale
  • on a larger scale, use carbon dioxide wastes from industrial processes that has been cleaned up before use
  • can use liquid carbon dioxide, applied through pipes, though this can be expensive
  • sometimes use fungi, grown as a mycelium in bags around the greenhouse, that add carbon dioxide through their respiration

  Concentration of carbon dioxide in greenhouses is often kept at around 0.1 per cent. Above one per cent, carbon dioxide changes cell pH –makes it more acidic –becomes toxic.
• Limiting factors?


  Factors that restrict the growth or abundance of a population.
• Uses of glucose?


  respiration, produce fat/oils in storage, stored as starch (insoluable), produce cellulose for cell walls and amino acids