photosynthesis

• word equation for photosynthesis

  carbon dioxide + water --> glucose + oxygen
• define photosynthesis

  a series of reactions that helps plants make food by converting light energy to chemical energy
• the carbon dioxide diffuses through tiny openings called stomata in the leaf
• Unused oxygen produces during the aerobic respiration leaves the plant through the stomata
• The water is transported through the xylem in vascular plants.
• Photosynthesis takes place in the chloroplasts
• where is chloroplast found?

  in leaves and other plant parts
• what does chloroplast contain?

  chlorophyll
• chlorophyll is a green pigment found in plant cells
• light energy is converted into chemical energy during photosynthesis
• what is starch


  a carbohydrate formed by many glucose molecules linked together to form a long chain
• light energy splits water into oxygen and hydrogen.
• hydrogen combines with carbon dioxide to form starch in the form of glucose
• chlorophyll captures sunlight
• what are the raw materials needed for photosynthesis

  light, carbon dioxide, water
• how do we prepare and test a leaf for starch?

  1. boil the leaf in boiling water to break down the cell membrane and stop all the chemical reactions in the leaf cell.
  2. soak boiled leaf in ethanol in hot water to remove chlorophyll so that any change in the colour of iodine solution will be visible
  3. wash leaf in hot water to soften it
  4. put few drops of iodine solution on the leaf
• brown iodine solution turns blue-black if starch is present
• ways to find out whether photosynthesis has taken place


  test a leaf for presence of starch / find out if oxygen gas was produced by plant
• water in the vacuoles keeps the cell firm and turgid
• vacuole swells and pushes against cell wall when water enters
• vacuole loses its shape and becomes flaccid when water is lost
• most of the water is lost by a process callled transpiration
• some reactants need to be dissolved in water before chemical reactions can take place
• explain the process of transpiration

  water moves from the roots through the plant before evaporating from the stem, leaves, flowers. the water then absorbs heat from the surroundings to change into water vapour which causes to make the surroundings cooler
• what is a phloem

  transport minerals/dissolved food minerals to other part of plant
• what are carnivorous/insectivorous plants?

  they consume insects or small animals
• carnivorous/insectivorous plants trap insect or small animals for nutrients
• mineral salts are nutrients for plants for healthy growth
• two types of fertilisers


  organic, inorganic
• organic fertilisers release mineral salts to the soil as decomposers act on them
• define inorganic fertilisers


  man-made fertilisers produced from chemicals. they contain various types of mineral salts
• inorganic fertilisers are also called chemical fertilisers
• how many kinds of mineral salts?

  4
• types of mineral salts


  nitrate, phosphorus, potassium, magnesium
• function of nitrate

  • nitrogen component necessary for pants to make proteins, DNA and chlorophyll
  • leaf development
  • growth and repair
  • deficiency that can lead to leaves turning yellow, and stunt growth
• function of phosphorus


  developments of roots, flowers, seeds, and fruits
• funtion of potassium

  • development of roots
  • resistance against diseases
  • promoting flowering and fruiting
• function of magnesium

  • making chlorophyll
  • prevent deficiency that can lead to leaves turning yellow