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PHOTOSYNTHESIS. Using Light to Make Food. Photosynthesis is the most important chemical process on earth because:. It provides food for virtually all organisms SWEET!!!!. BIG PICTURE: Photosynthesis .
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PHOTOSYNTHESIS Using Light to Make Food
Photosynthesis is the most important chemical process on earth because: • It provides food for virtually all organisms • SWEET!!!!
BIG PICTURE: Photosynthesis Light energy is used to make sugarand other food molecules from carbon dioxide and water
Chemical Reaction sunlight • 6 H2O + 6 CO2 ----------> C6H12O6+ 6 O2 How does this equation compare to the cell respiration one? Photosynthesis: An Overview of Photosynthesis (click)
7.1 AUTOTROPH • Autotrophs“Self-feeders” • Make their own food • Also referred to as: Producers= produce the biosphere’s food supply
Photosynthetic Plants Forests (land) Kelp (ocean) Diatoms (microscopic)
Is the opening carbon dioxide,oxygen. And water in/out 1. Stoma (sing.) in leaf lower epidermis Stomata (pl.)
Leaf CS 2. Upper Epidermis 4. Mesophyll-cells containing chloroplasts 3. Lower epidermis Covers and protects see stoma –in lower epidermis only
4. Mesophyll • = Palisade Layer + Spongy Layer
5. Cuticle Waxy, waterproof coating (to retain H2O)
6. Palisade Layer • cylindrical cells, vertically oriented, closely packed
7. Spongy Layer • cells are irregular in shape and loosely packed O2 ,CO2, H20 vapor go in/out
8. Guard Cells Control Stomata • Full guard cells(turgid) opens the stoma. • Flaccid (lost water) guard cells, the stoma closes. • ANIMATION: Stoma • What causes them to open?What goes into the stomata?
9. Plant Vein: Xylem + Phloem Xylem-(blue) carries water Phloem (thicker cell wall)-(yellow) carries food
Guard Cells Animations • LabBench (guard cell animation) • Another animation of opening and closing of guard cells http://academic.kellogg.cc.mi.us/herbrandsonc/bio111/animations/0021.swf (really nice)
Water Movement • LINK: http://www.sciencemag.org/sciext/vis2005/show/transpiration.swf
Photosynthesis in Elodea Lab See oxygen bubbles coming from the Elodea What conditions are best?
Elodea Bubbles Movie • sLowlife Exhibit
Stroma = thick fluid between the thylakoids thylakoids = disks within the chloroplasts granum=stack of thylakoids (grana pl.) Chloroplast Diagram
GRANA • What is the difference between grana and granum?
STROMA • So what’s the difference between the stoma and the stroma? • STOMA = opening in lower epidermis • STROMA = area around thylakoid disks in the chloroplast
Chloroplast Diagram Stromal lamella = connect grana D. Outer Membrane Thylakoid membrane Inner Membrane Thylakoid space Intermembrane Space
Note the stacks of thylakoid disks =grana Note area between = stroma Chloroplasts TEM
Nice Little Photosynthesis Movies • VCAC: Cellular Processes: Photosynthesis: The Movie • VCAC: Cellular Processes: Photosystem II: The Movie
Light Dependent Reaction (LDR) Converts light energy to chemical energy + O2 Light Independent Reaction (LIR) Assembles sugar molecules using CO2 What happens here?
Light Dependent Reaction LDR Uses light energy Light Independent Reaction LIR (Calvin Cycle) uses ATP and NADPH (from LDR) Where does energy come from?
PSI and PSII • PSI and PSII animation • Another PSI and PSII animation
LDR occurs in thylakoid membranes of chloroplast’s grana LIR (aka Calvin cycle) occurs in stroma of chloroplast Where is it located in the cell?
LDR ATP and NADPH Also O2 LIR sugar Final Products of Each?
NEW VOCAB. WORD • Carbon fixation = • incorporation of carbon into an organic molecule (useable) • EXAMPLE: CO2 into C6H12O6 FIXATION = make in a usable form
LIGHT • CHLOROPHYLL
Pigments in Plants • Pigments are light-absorbing molecules • Different pigments absorb or reflect different colors
wavelengths absorbed: blue-violet andred Reflects: grass green Chlorophyll a Wavelength
Absorbs: blue and orange Reflects: yellow-green An accessory chlorophyll in plants Chlorophyll b
Absorb: blue-green Reflect: yellow-orange Other pigments in plants Carotenoids-orange
As fall comes there are shorter days of sunlight Less photosynthesis means less food for plants. Chlorophyll breaks down and exposes the other colors that were there all along, but were masked by the green chlorophyll. FYI Why do leaves change color?
DO WORKSHEET • “Absorption of Chlorophyll” • Photosynthesis: The Action Spectrum for Photosynthesis (experiment link)
7.7Electromagnetic • Photosynthesis: Electromagnetic Energy • (move the arrow)