BIOL2043 - Handout 4 - Photosynthesis.pdf - BIOL 2043 Photosynthesis Photosynthesis DR BONNY B H YUEN HANDOUT 4 2015-2016(SEMESTER 1 ENVIRONMENTAL

BIOL2043 - Handout 4 - Photosynthesis.pdf - BIOL 2043...

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Photosynthesis D R . B O N N Y B . H . Y U E N H A N D O U T 4 2 0 1 5 - 2 0 1 6 ( S E M E S T E R 1 ) E N V I R O N M E N T A L S C I E N C E P R O G R A M M E BIOL 2043 Photosynthesis
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Review on previous lectures 2 Cell structure and function Organelles Ribosomes Endomembrane system Golgi apparatus Energy related organelles Chloroplasts Mitochondria Cytoskeleton Membrane structure and function Membrane proteins
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Outline 3 Photosynthetic Organisms Flowering plants as photosynthesizers Photosynthetic processes Light Reactions Capture light Calvin Cycle Reactions (“dark reactions”) Reduce CO 2 to carbohydrates Explain the different mechanisms employed by C3, C4 and CAM plants
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Photosynthetic Organisms 4 All life on Earth depends on a star 93 million miles away (solar energy) Photosynthetic organisms algae, plants, cyanobacteria solar energy carbohydrates autotrophs produce their own food
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Photosynthetic Organisms 5 Photosynthesizers produce all food energy Only 42% of sun’s energy directed towards earth reaches surface Of this, only 2% is captured by photosynthesizers Of this, only a tiny portion results in biomass
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Photosynthesis 6 Photosynthesis takes place in the green portions of plants Leaf of flowering plant contains mesophyll tissue Cells containing chloroplasts photosynthesis mesophyll chloroplast
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Photosynthesis 7 Raw materials for photosynthesis: CO2 and H2O Roots absorb water that moves up vascular tissue CO2 enters a leaf through small openings called stomata stomata
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Photosynthesis 8 CO 2 + 6H 2 O C 6 H 12 O 6 (sugar) + 6O 2 Energy supplied by light Chlorophyll absorbs solar energy and energize electrons prior to reduction of CO2 to a carbohydrate
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Leaves and Photosynthesis 9 Grana Chloroplast Leaf cross section granum independent thylakoid in a granum mesophyll Lower epidermis ipper epidermis cuticle leaf vein outer membrane inner membrane thylakoid space thylakoid membrane overlapping thylakoid in a granum CO 2 O 2 stomata stroma stroma 37,000 X
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Photosynthetic Pigments 10 Pigments: Chemicals that absorb some colors in rainbow more than others Colors least absorbed reflected most Pigments found in chlorophyll absorb more reds and blue light than green light
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