The Working Cell: Energy from Sunlight

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The Working CellEnergy from Sunlight

• Chapter 8 Notes

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Ch. 8 The Working Cell Energy from Light

• 8.1 Photosynthesis uses light energy to
  make food.
• 8.2 The light reactions convert light
  energy to chemical energy.
• 8.3 The Calvin cycle makes sugar from carbon
  dioxide.
• 8.4 Photosynthesis has a global impact.

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8.1 Photosynthesis uses light energy to
make food.

• Objectives
• Describe the structure of a chloroplast.
• Identify the overall reactants and products of
  photosynthesis.

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8.1 Photosynthesis uses light energy to
make food.

• Key Terms
• Chloroplast
• Chlorophyll
• Stroma
• Thylakoid
• Light reactions
• Calvin cycle

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8.1 Photosynthesis uses light energy to
make food.

• Photosynthesis is the process by which plants
  other producers convert energy of sunlight to
  energy stored in organic molecules.
• Chloroplast organelle where photosynthesis
  takes place
• Chlorophyll chemical that gives a green color
  to chloroplasts.

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8.1 Photosynthesis uses light energy to
make food.

• Chloroplasts structure is key to its function
• Has an inner outer membrane
• Inner membrane encloses a thick fluid called the
  stroma
• Suspended in the stroma are thylakoids
  disk-shaped sacs

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8.1 Photosynthesis uses light energy to
make food.

• Cellular respiration fall of electrons form
  glucose to oxygen gives off energy, which is then
  used to make ATP.
• Photosynthesis is the opposite electrons from
  water are boosted uphill by the energy from
  sunlight.

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8.1 Photosynthesis uses light energy to
make food.

• Excited electrons along with carbon dioxide
  water are used by chloroplasts to produce glucose
  oxygen.

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8.1 Photosynthesis uses light energy to
make food.

• Photosynthesis occurs in 2 main stages.
• Light reactions convert sunlight to chemical
  energy
• Stored in NADPH ATP
• Calvin cycle makes sugar from carbon dioxide
  and H ions from the splitting of water.

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8.1 Concept check (QUIZ)

• Draw label a simple diagram of a chloroplast
  that includes the following structures outer
  inner membranes, stroma, thylakoids.
• What are the reactants of photosynthesis, what
  are the products?
• Name the 2 main stages of photosynthesis. How
  are they related?

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8.2 The light reactions convert light energy
to chemical energy

• Objectives
• Explain how light interacts with pigments.
• Describe how photosystems help harvest light
  energy.
• Identify the chemical products of the light
  reactions.

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8.2 The light reactions convert light energy
to chemical energy

• Key Terms
• Wavelength
• Electromagnetic spectrum
• Pigment
• Paper chromatography
• photosystem

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8.2 The light reactions convert light energy
to chemical energy

• Light energy is a form of electromagnetic energy
• Travels in waves (similar to ocean waves)
• Measured by wavelength distance between 2
  adjacent waves.

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8.2 The light reactions convert light energy
to chemical energy

• Different forms of electromagnetic energy have
  characteristic wavelengths
• Electromagnetic spectrum the range of types of
  electromagnetic energy

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8.2 The light reactions convert light energy
to chemical energy

• Pigments chemical compounds that give a
  substance its color.
• Cause different wavelengths to be
• Absorbed
• Transmitted
• Reflected

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8.2 The light reactions convert light energy
to chemical energy

• Paper chromatography lab technique used to
  observe different pigments in substances.

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8.2 The light reactions convert light energy
to chemical energy

• Harvesting light energy
• Photosystems clusters of pigment molecules
• Chlorophyll a
• Chlorophyll b
• Carotenoids

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8.2 The light reactions convert light energy
to chemical energy

• Harvesting light energy
• 1)Pigments absorb light energy
• 2)transfer energy to electrons
• 3)transfer energy to electronacceptor.
• 4)converts to ATP or NADPH.

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8.2 The light reactions convert light energy
to chemical energy

• Chemical products of the light reactions
• Oxygen, released as a waste product of the 1st
  photosystem.
• ATP produced by the release of energy by the
  electron transport chain between photosystems.
• NADPH produced by the second photosystem

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8.2 Concept check

• Explain why a leaf appears green.
• Describe what happens when a molecule of
  chlorophyll a absorbs light.
• Besides oxygen, what 2 molecules are produced by
  the light reactions?
• Where in the chloroplast do the light reactions
  take place?

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8.3 The Calvin cycle makes sugar from
carbon dioxide

• Objectives
• Explain how the Calvin cycle makes sugar.
• Summarize the overall process of photosynthesis.

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8.3 The Calvin cycle makes sugar from
carbon dioxide

• The Calvin cycle
• Called a cycle because the starting material RuBP
  is regenerated each time the process occurs
• RuBP is a 5 carbon sugar

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8.3 The Calvin cycle makes sugar from
carbon dioxide

• Into the Calvin cycle
• Carbon dioxide
• ATP
• NADPH

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8.3 The Calvin cycle makes sugar from
carbon dioxide

• Outputs of Calvin cycle
• G3P (an energy rich sugar)
• Not yet glucose
• Used by plant to make glucose
• ADP P
• NADP

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8.3 The Calvin cycle makes sugar from
carbon dioxide

• Summary of photosynthesis
• Light reactions
• Convert light energy to chemical energy
• Occurs in thylakoids
• Uses water (reactant) releases oxygen (product)

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8.3 The Calvin cycle makes sugar from
carbon dioxide

• Calvin cycle
• Occurs in stroma
• Uses ATP NADPH
• Converts carbon dioxide (reactant) to sugar
  (product)

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8.3 Concept check

• What are the inputs outputs of the Calvin
  cycle?
• Which stage of photosynthesis uses each reactant
  from the overall photosynthesis equation? Which
  stage generates each product from the overall
  photosynthesis equation?

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8.3 Concept check

• Why is the Calvin cycle called a cycle?
• What molecule is the direct product of
  photosynthesis? How is that molecule then used
  by the plant cell?

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8.4 Photosynthesis has a global impact.

• Objectives
• Describe the path of carbon in the carbon cycle.
• Explain how photosynthesis is related to climate.

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8.4 Photosynthesis has a global impact.

• Key Terms
• Carbon cycle
• Greenhouse effect

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8.4 Photosynthesis has a global impact.

• Processes that occur on a global scale depend on
  chloroplasts mitochondrion
• Carbon cycle process by which carbon moves from
  inorganic to organic back to inorganic.

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8.4 Photosynthesis has a global impact.

• Path of carbon in the carbon cycle
• Producers convert inorganic carbon to organic
  carbon through photosynthesis.
• Consumers eat the producers, may be eaten by
  other consumers.
• Cellular respiration by both producers
  consumers eventually carbon dioxide to the
  atmosphere

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8.4 Photosynthesis has a global impact.

• Plants other photosynthetic organisms make
  about 160 billion metric tons of organic
  material.
• 80 trillion copies of book
• 25 stacks reaching to the sun.

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8.4 Photosynthesis has a global impact.

• Carbon dioxide in the atmosphere traps in heat
  greenhouse effect
• Keeps world climate warm enough for living
  things.
• Average 10C warmer than it would be.
• Amount of carbon dioxide in atmosphere is rising.

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Photosynthesis
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Stages of Photosynthesis
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Electromagnetic spectrum
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Pigments Color
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Harvesting Light Energy
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Chemical products of light reactions
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Calvin cycle
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Photosynthesis
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Greenhouse effect
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Light Waves