Test 2 study guide

Test 2 study guide - Jonathan Spear Biology Study Guide...

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Jonathan Spear Biology Study Guide: Test 2 Metabolism and Photosynthesis2 Every organism relies on the energy from plants Photosynthesis: 1. Done by autotrophic plants 2. Makes food (sugar) from inorganic CO2 and energy from the sun 3. Energy from the sun is used by autotrophs (plants) 4. 12H20+6CO2-------6O2+C6H12O6+6H20 Light-dependent reactions —conversion of solar energy into chemical energy Light-independent reactions (calvin cycle)—synthesis portion of the process where CO2 is incorporated into sugars (carbon fixation) using the chemical energy from light reactions In light-dependent reactions energy from the sun is absorbed by plants and converted into chemical energy Chemical Energy = ATP and NADPH (electron carrier—energy storage) The most photosynthetic part of a plant are the leaves Photosynthesis takes place inside the thylakoids, which are located in the chloroplasts. Light energy travels in wavelengths—shorter wavelength means more energy Pigments are special molecules that absorb light There are different colored pigments 1.Cholorphyll b—green 2. Carotenoids—Orange 3.Xanthophylls—yellow or brown 4. Anthocyanins—purple Same colors bounce off Chlorophyll is in the chloroplast of plant cells (embedded in the internal thylakoid membranes). This is the most important pigment in absorbing light Leaves change color because of less energy and chlorophyll Chlorophyll molecules are arranged into an “antenna” in photosystems within the thylakoids Protons are units of light Light hits the photosystems and electrons get excited and jump up which releases energy. This energy gets passed on to other molecules—fluorescence Photosystems have two pathways (that work together) in the light-dependent reactions that ultimately transfer energy to ATP and NADPH Photosystem II comes first and then photosystem I ATP is made by chemiosmosis 1. Energy from excited electrons is transferred to ATP indirectly 2. Chlorophyll’s excited electrons are excited by light to a high energy level
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3. Excited electrons are passed down an electron transport chain (ETC) in thylakoid membranes 4. Energy gets released as electrons move down ETC 5. This energy pumps H+ across membrane (into the thylakoids) and builds up a concentration gradient 6. Energy is released as H+ flows out of the thylakoid through ATP synthase—this helps make ATP Going through the ATP synthase and adding a phosphate creates ATP PS II electrons are used to make ATP, then go to PS I. Water supplies electrons to PS II (H20 splits, donating electrons) PS I electrons are used to make NADPH The calvin cycle produces glucose and gives off CO2 (light—independent reaction) Cellular Respiration Cellular respiration- chemical reactions break down fuel (food) molecules to extract energy Most organisms go through cellular respiration Aerobic respiration requires oxygen Anaerobic respiration
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This note was uploaded on 04/08/2008 for the course BI 100 taught by Professor Osborne during the Spring '08 term at Butler.

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Test 2 study guide - Jonathan Spear Biology Study Guide...

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