SB6a- Photosynthesis

• What is photosynthesis?

  Process that plants and algae use to make their own food. This makes plants producers.
• Explain why photosynthetic organisms are producers of biomass

  Photosynthetic organisms are the main producers of food and therefore biomass
• What is biomass?

  Mass of living material at a particular stage in a food chain
• What is the word equation for photosynthesis?

  Carbon dioxide + water —> glucose + oxygen
• What is the symbol equation for photosynthesis?

  6CO2 + 6H2O -> C6H12O6 + 6O2
• What energy does photosynthesis use?

  Light energy: is absorbed by chlorophyll, which transfers to chemical energy stored in sugars produced.
• Why is photosynthesis an endothermic reaction? (reaction that absorbs heat)

  Energy is transferred from the environment to chloroplasts by light, and requires energy from the sun.
• What is glucose used for in plants?

  • cellular respiration
  • making something out of glucose
  • Making amino acids
  • Making oils and fats
• What cellular respiration does for the plant

  Cellular respiration breaks glucose down to release energy when photosynthesis traps the suns light energy. This is done by cells to release energy when needed.
• What things does the plant make things out of glucose?

  • the plant can make cellulose, which is a complex carbohydrate which can strengthen the cell walls
  • or starch which has no particular function, but is compact and insoluble which plants store to break down into glucose later , as starch wont draw water in through osmosis. This is mostly done when photosynthesis isnt done much eg. in the night: winter
• Why is glucose used to make amino acids?

  Amino acids are made by combining glucose molecules and nitrate ions found in the soil.

  Amino acids allow proteins to be made for the plant
• Why is glucose used to make fats and oils?

  They are made to be stored as a future energy source, which is mainly needed when making seeds
• What is a plants growth rate dependent on?

  How fast it can photosynthesise as glucose is essential for plants
• Where do plants get their reactants from?

  • Carbon dioxide diffuses through the leaves through the stomata
  • Water is taken up by the roots from the soil, and is diffused into the root hair cells by osmosis. It is then transported to the leaves by the xylem
• What adaptions does the leaf have for photosynthesis?

  • Has a large surface area to absorb more light
  • Has a stomata (tiny holes on the skin of the leaf) to allow carbon dioxide into the leaf and oxygen out.
  • The leaf is thin, so there is a short distance for carbon dioxide to diffuse into leaf cells
  • Network of veins to support the leaf and transport water and mineral ions
  • Waxy coating of cuticle to prevent waterloss by evaporation
• What is the thin epidermis function?

  To allow more light to reach palisade cells
• What is the thin cuticle made out of wax’s function?

  To protect the leaf from infection, and prevent waterloss without blocking out light
• What is the spongy mesophyll layer’s function?

  It has air spaces to allow gases to diffuse through the leaf
• What is the Palisade cell layer’s function?

  It is at the top of the leaf, to absorb more light and increase the rate if photosynthesis