Where does oxygen come from

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Where does oxygen come from?

• Photosynthesis

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What is Photosynthesis?

• Metabolic pathway that converts light energy into
  chemical energy
• Chemical energy is produced in for of sugar (
  Sucrose, glucose or starch)

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Why is photosynthesis important?

• Nearly all life on Earth either directly or
  indirectly depends on it as a source of energy

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Prime materials for Photosyntesis
LIGHT
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Nature of light why are most leaves green?
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MAIN PIGMENT CHLOROPHILL
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Accessory Pigments and Action Spectrum
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General process
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Light Reactions (light dependent)
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Production of ATP
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Light Reactions
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Calvin cycle
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Calvin cycle

• RuBP (5 carbons) accepts the atmosferic CO2 and
  then is split in two molecules of 3 carbons each
• These molecules of 3 carbons are phosphorilated
  and are then linked together to make a molecule
  of 6 carbons? Glucose

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Calvin Cycle
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In General

• In the Light Dependent Processes (Light
  Reactions)
• light strikes chlorophyll a in such a way as to
  excite electrons to a higher energy state.
• Energy is converted (along an electron transport
  process) into ATP and NADPH.
• Water is split in the process, releasing oxygen
  as a by-product of the reaction.
• The ATP and NADPH are used to make C-C bonds in
  the Light Independent Process (Dark Reactions).

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In General

• In the Light Independent Process (Calvin cycle)
• CO2 from the atmosphere (or water for
  aquatic/marine organisms) is captured by the
  stomata in the leaves
• CO2 is modified by the addition of Hydrogen to
  form carbohydrates (general formula of
  carbohydrates is CH2On).
• The incorporation of CO2 into organic compounds
  is known as carbon fixation.
• The energy for this comes from the first phase of
  the photosynthetic process.

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General equation

• Carbon dioxide Water Sunlight Sugar
  Oxygen
• or
• 6 CO2 6 H20 Energy gt C6H1206 6 02

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And what happens with the sugar produced?
GLUCOSE
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