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30 Cards in this Set
- Front
- Back
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What is Photosynthesis?
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-Photosynthesis is the process
that converts solar energy into chemical energy -Directly or indirectly, photosynthesis nourishes almost the entire living world |
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Autotrophs
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-Autotrophs sustain themselves by
creating their own organic material |
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Heterotrophs
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-Heterotrophs obtain their organic
material from other organisms |
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Auto versus Hetero
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-Autotrophs are the producers of
the biosphere, producing organic molecules from CO2 and other inorganic molecules -Almost all plants are photoautotrophs, using the energy of sunlight to make organic molecules from H2O and CO2 -Heterotrophs are the consumers of the biosphere -Almost all heterotrophs, including humans, depend on photoautotrophs for food and O2 |
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Overall Reaction
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6 CO2 + 6 H2O + light energy------> C6H12O6 + 6 O2
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Overall Reaction
(What does this remind you of?) |
It is the EXACT OPPOSITE of cellular respiration!
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Overall Reaction
(Includes) |
1) Light Reaction
-Light energy + H2O -----> Chemical Energy (ATP & NADPH) + O2 2) Calvin Cycle -Chemical energy (ATP and NADPH) + CO2 ----->C6H12O6 |
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Photosynthesis Coenzyme
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-NADP+ (nicotinamide adenine
dinucleotide phosphate) -Carrier ion -It picks up a H+ and excited electron to become NADPH -The H+ and electron move to the Calvin Cycle |
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Photosynthesis (Reactants)
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-6CO2
-6H2O -Light energy |
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Photosynthesis (Products)
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-C6H12O6 (glucose)
-O2 |
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Photosynthesis in a Leaf
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-Leaves are the major locations of
photosynthesis -Their green color is from chlorophyll, the green pigment within chloroplasts -Light energy absorbed by chlorophyll drives the synthesis of organic molecules in the chloroplast |
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Photosynthesis in a Leaf (Part 2)
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-CO2 enters and O2 exits the leaf
through microscopic pores called stomata -Chloroplasts are found mainly in cells of the mesophyll, the interior tissue of the leaf -A typical mesophyll cell has 30–40 chloroplasts |
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Chloroplast
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-Thylakoids
-Interconnected sacs inside chloroplasts -Stacks of thylakoids are called grana |
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Chloroplast Part 2
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-Contain photosynthetic pigments
-Chlorophyll (give leaves green color) -Accessory pigments: carotenoids, phycocyanins |
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Chloroplast Part 3
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-Stroma
-Fluid inside the chloroplasts surrounding the thylakoids |
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Photosynthesis is a redox process in which H2O is oxidized and CO2 is reduced
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-Chloroplasts split H2O into hydrogen
and oxygen -Electrons of hydrogen are put into sugar molecules |
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Overview in Words
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Photosynthesis consists of the light reactions (the photo part) and Calvin cycle (the synthesis part)
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The light reactions (in the thylakoids)
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-Split H2O and release O2
-Reduce NADP+ to NADPH -Generate ATP from ADP by photophosphorylation |
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The Calvin cycle (in the stroma)
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-Forms sugar from CO2, using ATP
and NADPH -The Calvin cycle begins with carbon fixation, incorporating CO2 into organic molecules |
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Light Energy
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-Light is a form of electromagnetic
energy, also called electromagnetic radiation -Light travels in rhythmic waves |
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Wavelength
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-Wavelength determines the type of
electromagnetic energy -Wavelength is the distance between crests of waves |
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Electromagnetic Spectrum
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-The electromagnetic spectrum is the
entire range of electromagnetic energy, or radiation |
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Visible Light
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-Visible light consists of wavelengths
(including those that drive photosynthesis) that produce colors we can see |
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Photons
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-Light also behaves as though it
consists of discrete particles, called photons |
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Pigments
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-Pigments are substances that absorb
visible light -Different pigments absorb different wavelengths |
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Photons & Pigments
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-Wavelengths that are not absorbed
are reflected or transmitted -Leaves appear green because chlorophyll reflects and transmits green light |
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Spectrophotometer
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-A spectrophotometer measures a
pigment’s ability to absorb various wavelengths |
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Absorption Spectrum
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-An absorption spectrum is a graph
plotting a pigment’s light absorption versus wavelength -The absorption spectrum of chlorophyll a suggests that violet-blue and red light work best for photosynthesis |
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Action Spectrum
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-An action spectrum profiles the
relative effectiveness of different wavelengths of radiation in driving a process -Chlorophyll a is the main photosynthetic pigment |
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Accessory Pigments
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-Accessory pigments, such as
chlorophyll b, broaden the spectrum used for photosynthesis -Accessory pigments called carotenoids absorb excessive light that would damage chlorophyll |
