Photosynthesis and Cell Respiration

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Photosynthesis and Cell Respiration
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How do organisms obtain energy?

• Autotrophs
• Able to produce their own food
• Ex. Plants use sunlight to produce energy
• Photosynthesis
• Heterotrophs
• Unable to produce their own food, rely on other
  organisms as a source of energy
• Ex. Animals need to eat to survive
• Cellular Respiration

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Organisms rely on PHOTOSYNTHESIS and CELLULAR
RESPIRATION for their energy needs
Heat
Sunlight
Cellular respiration
Photosynthesis
Visual Summary 6.1
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Photosynthesis!

• What happens during photosynthesis?
• Plants (autotrophs) use energy from sunlight to
  convert water and carbon dioxide into
  carbohydrates (energy) and oxygen
• 6CO2 6H2O (light) ? C6H12O6 6O2
• Reactants?
• Carbon dioxide (CO2) and Water (H2O)
• Products?
• GlucoseSugar (C6H12O6) and Oxygen (O2)

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Photosynthesis Light and Pigment

• In addition to water and carbon dioxide,
  photosynthesis needs light and chlorophyll (a
  molecule in chloroplasts)
• Light is converted into chemical energy
• Occurs in chloroplasts
• Chlorophyll absorbs the light (it makes plants
  green!)

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The Two Parts of Photosynthesis

• Light-dependent reactions
• Need light to happen
• Occurs in Chloroplast
• Produces Oxygen
• Light-independent reactions (Calvin Cycle)
• Does not need light
• Use energy molecules (NADPH) to produce sugars
  for the plant

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Cellular Respiration

• Heterotrophs need to consume other organisms in
  order to survive
• Glucose (sugar) is a main source of this energy

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Cellular Respiration

• Cellular respiration is the process that
  releases energy by breaking down food molecules
  (glucose) in the presence of oxygen
• 6O2 C6H12O6 ? 6CO2 6 H2O Energy
• Oxygen glucose ? carbon dioxide water
  energy
• Compare this to the equation for
  photosynthesis.what do you notice?

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Cellular Respiration

• Occurs in three different steps
• Glycolysis one molecule of glucose is split in
  half
• Occurs in the cytoplasm
• Krebs Cycle the half-glucose molecules are
  broken down into carbon dioxide
• Occurs in the Mitochondria
• Electron Transport high energy electrons are
  used to produce energy for the cell
• Occurs in the Mitochondria

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