Photosynthesis + required practical

• Photosynthesis required practical (investigating light intensity):

  1. Set up a boiling tube contained sodium hydrogen carbonate, which will provide the pondweed with a constant supply of CO2.
  2. Place the pondweed inside of the boiling tube using tongs.
  3. Position the boiling tube so that it is 10cm away from the LED light source.
  4. Count the number of bubbles emerging from the cut end of the stems in one minute and record your results.
  5. Repeat the experiment five times, moving the boiling tube away from the light source.
• Photosynthesis required practical (investigating light intensity):

  Independent variable: light intensity/ distance from light source

  Control variable: concentration of sodium hydrogencarbonate (CO2), temperature and the type of pondweed

  Dependent variable: the number of bubbles produced each minute
• Photosynthesis required practical risk:

  Ensure hands are dry before handling the electric LED light source.
• The chemical equation for photosynthesis is:

  6CO2+ 6H2O —> C6H1206 + 602
• The equation for photosynthesis is:

  carbon dioxide + water —> glucose + oxygen
• Photosynthesis is an endothermic reaction.
• Photosynthesis is an endothermic reaction because it takes in light from the surroundings.
• What does letter A represent?

  The waxy cuticle.

  
• What does letter B represent?

  Upper epidermis.

  
• What does letter C represent?

  The palisade mesophyll layer.

  
• What does letter D represent?

  The spongy mesophyll layer.

  
• What does the letter E represent?

  The lower epidermis.

  
• What does letter F represent?

  Stomata.

  
• What does the letter G represent?

  The guard cells.

  
• What does the letter H represent?

  The phloem.

  
• What does the letter I represent?

  The xylem.

  
• Translocation is the movement of substances in a plant.
• The xylem are tubes that allow water and minerals to move up the plant.
• The phloem are tubes that allow sugars to move around the plant.
• When there are low levels of water in a plant, the guard cells become flaccid and the stoma closes. This is to prevent further water loss.
• When there are high levels of water in plants, the guard cells become turgid and the stoma opens. This is to allow water to escape but also to let carbon dioxide inside.
• A transpiration stream is the movement of water through the xylem tissue and mesophyll cells.
• Transpiration is the loss of water from the leaves of a plant through evaporation.
• Glucose produced in photosynthesis may be used:

  • in respiration
  • to produce amino acids for protein synthesis
  • to produce cellulose to strengthen the cell wall
  • converted into insoluble starch for storage
  • produce fat or oil for storage