Photosynthesis

• Define Photosynthesis:

  The process whereby light energy from sunlight is converted into chemical energy to synthesise large organic molecules from simple inorganic molecules
• Chloroplast is the site of photosynthesis
• In which organ of the plant does photosynthesis take place?

  Leaf
• Name the products of photosynthesis:

  • Glucose
  • Oxygen
• Name the reactants of photosynthesis:

  • Carbon dioxide
  • Water
• Word equation for Photosynthesis:

  Carbon dioxide + Water --- Light energy ---> Glucose + Oxygen
• Chemical equation for Photosynthesis:

  6 CO2 + 6 H2O --- Light energy ---> C6H12O6 + 6 O2
• Define Photon:

  A particle of light containing a certain amount of energy
• How are photosynthesis and respiration related?

  Carbon dioxide (CO2) and water (H2O) are the raw materials for photosynthesis and the products of respiration.

  Oxygen (O2) and glucose (C6H12O6) are the raw materials for respiration and the products of photosynthesis.

  Oxygen is used as the final electron acceptor in respiration.

  ATP is produced to provide energy for cell activities

  Decomposing plant materials provide mineral ions.
• State the features of Chloroplasts:

  • Chloroplast envelope
  • Stroma
  • Grana (thylakoids)
  • intergranal lamellae
  • Starch grains
  • chlorophyll
• Chloroplasts are 4 - 10 μm long
• Chloroplasts are abundant in which cells?

  Palisade cells
• The first stage of photosynthesis is called the light dependant stage.

  The second stages of photosynthesis is called the light independent stages.
• What types of reaction is photosynthesis?

  • Endothermic
  • Reduction
• What is the first stage of photosynthesis called?

  Light dependant stage
• What is the second stage of photosynthesis called?

  Light independent stage
• What is the stroma?

  The fluid filled matrix within chloroplasts
• Which stage of photosynthesis is the Stroma involved in?

  Light independent / second
• Carbon fixation helps regulate the concentration of carbon dioxide in the atmosphere and oceans
• Describe the structure of chloroplasts:

  • Chloroplast envelope = controls the entry and exits of materials
  • Stroma = fluid filled matrix, contains ribosomes, starch grains, enzymes, DNA
  • Grana = stacks of thylakoids, large surface area
  • thylakoids = stacks of flattened membrane sacs
  • intergranal lamellae = extensions that run from one granum to the next
  • chlorophyll = green primary pigment
• Where does the light independent stage of photosynthesis take place?

  Stroma
• Where does the light dependent stage of photosynthesis take place?

  Grana
• One granum may contain up to 100 thylakoids
• Name the by-product of photosynthesis.

  Oxygen
• State factors determining the rate of photosynthesis.

  • Carbon dioxide concentration
  • Temperature
  • Light intensity
  • Water
• The light independent reaction in photosynthesis is also known as the Calvin Cycle
• Photosystems within thylakoids contain photosynthetic pigments
• Plants, algae and some bacteria that photosynthesise are referred to as Autotrophs
• Name the two types of chlorophyll:

  • Chlorophyll a
  • Chlorophyll b
• Each photosynthetic pigment absorbs light energy of a particular wavelength and reflects others. The energy absorbed is funnelled down to the primary pigment reaction centre.
• Outline the two types of photosynthetic pigments:

  • Primary pigments
  • Accessory pigments
• Name a primary pigment:

  Chlorophyll a
• What colour of light does Chlorophyll a absorb?

  Red (some blue )
• There are two types of photosystems:

  • Photosystem I
  • Photosystem II
• Each photosystem contains a different combination of chlorophyll a pigments
• Chlorophyll a appears blue green

  Chlorophyll b appears yellow green
• Name two accessory pigments:

  • Caretenoids
  • Xanthophylls
• What colour of light does Carotenoids absorbs?

  Blue
• What colours of light does Xanthophylls absorb?

  Blue and green
• Where are the photosystems situated?

  Thylakoid membrane