Storing Energy from the Sun: Photosynthesis

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Storing Energy from the Sun Photosynthesis
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Plant ImpostorsIn The News
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Photosynthesis

• Process that captures energy from the sun
• Energy stored in carbohydrates
• Oxygen is byproduct

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Sunlight

• Electromagnetic energy (radiation)
• Packets of energy (photons)
• Range of wavelengths

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Plant Pigments

• Found in chloroplasts
• Absorb some visible wavelengths

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Plant Pigments

• Carotenoids absorb photons of green,
• blue violet wavelengths
• Chlorophylls absorb photons of red
• violet-blue wavelengths

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Autotrophs

• Produce their own food
• Photosynthesis
• Chemosynthesis

Cyanobacteria
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Photosynthetic Autotrophs

• Solar energy powers glucose synthesis
• Uses
• Carbon dioxide
• Water
• Captured energy
• Produces
• Glucose
• Oxygen

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Heterotrophs

• Consume other organisms
• Cannot produce their own food
• Food ultimately comes from autotrophs

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Cellular Respiration

• Process that unlocks stored energy
• Nutrient molecules store energy in bonds
• Chemical reactions produce ATP
• ATP provides cellular energy

Skunk cabbage using metabolic heat to melt snow
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Aerobic Cellular Respiration

• Oxygen dependent

• Byproducts
• Raw materials for photosynthesis
• Carbon dioxide
• Water

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Carbohydrates

• Photosynthetic stored energy product

energy
6CO2 6H2O C2H12O6 6O2
Carbon dioxide water with energy yields glucose
oxygen
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Chemical Reactions for Photosynthesis

• Light dependent reactions
• Light independent reactions

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Light Dependent Reactions

• ATP NADPH formed
• NADPH
• Nicotinamide adenine dinucleotide phosphate
• An electron carrier
• Molecules store energy from sun

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Electron Carrier

• Transfer from one molecule to another
• Produce molecules that carry energy

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Light Independent Reactions

• Provides for formation of glucose
• Uses ATP NADPH
• No direct light involvement

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Chloroplasts

• Organelles
• Site of photosynthesis
• Light dependent reactions on membrane
• Light independent reactions in fluid

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Chloroplasts

• Probably evolved from symbiotic bacteria
• Thylakoids internal membranes
• Grana stacks of thylacoids
• Stroma fluid around thylakoid

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Summary of Photosynthesis

• Light dependent reactions change energy from Sun
  into chemical energy
• Energy is held in ATP NADPH
• Chemical energy from ATP NADPH is transferred
  to sugars
• Sugars used to fuel activities of life

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Reactions to Store Energy

• Pigment molecules funnel energy to chlorophyll
• Two stage photosystem to carry out light
  dependent reactions
• Photosystems work together to harvest energy

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Pigment Molecules

• On thylakoid membranes
• Chlorophyl (chlorophyl a)
• Capture funnel photon energy

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Photosystems

• Electrons boosted to higher level
• Photosystem I
• Energy transferred to P700 molecule
• Photosystem II
• Energy transferred to P680 molecule

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Electron Flow in Photosynthesis
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Electron Flow in Light-Dependent Reactions
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Carbohydrate Production Light-Independent
Reactions
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