photosynthesis and plants 6co 2 + 6h 2 o + sunlight c 6 h 12 o 6 + 6o 2 epidermis with cuticle ...
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Chloroplast anatomyTRANSCRIPT
Photosynthesis and Plants
6CO2 + 6H2O + sunlight C6H12O6 + 6O2
Epidermis with cuticle palisade mesophyll – parenchymal cells – primary sites
of photosynthesis Spongy mesophyll – CO2 exchange Vascular bundles – xylem and phloem for water and
sugar transport Lower epidermis with stomata and guard cells
Cross section of leaf
Chloroplast anatomy
Reactions of Photosynthesis
Light reactions Dark reactions – Calvin cycle
Light Reaction
Photons strike thylakoid membrane activating chlorophyll and electrons from water
Excited electrons move down electron transport chain ATP and NADPH are produced
Antenna complex
Chlorophyll a, b, and carotenoids
Pigments gather light Reaction ctr. “excites”
electrons light reactions
Non-cyclic Photophosphorylation
Cyclic Photophosphorylation
Simple way to create ATP Photons absorbed in PS I
(700) Electrons excited Passed down cytochrome
ETS ATP generated, electrons
passed back to PS I No NADPH No photolysis
Dark Reactions
Use ATP, CO2, and NADPH to create sugars
Calvin cycle
Photorespiration
Rubisco starts to bind oxygen because CO2 availability is limited
C4 alternative – CO2 combines with PEP to form oxaloacetate (4 Carbon sugar)
PEP carboxylase (enzyme that catalyzes C4 rxn.) has high affinity for CO2.
Oxaloacetate converts to malate and shuttled to bundle sheath cells
CO2 released for use in Calvin cycle CAM alternative is day/night cycle
C4 photosynthesis
CAM photosynthesis