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CH: 7 The Working Cell: Energy from Food 7.1 Sunlight Powers Life Compare and contrast how autotrophs and heterotrophs obtain food. Compare: Both get energy from organic compounds Contrast: More Info: Autotrophs convert inorganic molecules into organic molecules Autotrophs make their On land= mostly plants own organic compounds In water= algae Heterotrophs get organic Autotroph=Producer compounds by consuming Heterotroph=Consumer autotrophs Explain how cellular respiration harvests the energy in food. Cellular Respiration: Chemical Process Changes organic compound into ATP Requires oxygen ATP is used by cells for: energy Which cells? ALL CELLS perform cellular respiration Key Terms autotroph photosynthesis producer heterotroph consumer cellular respiration Concept Check 7.1 1. Define autotroph and heterotroph, and give an example of each. 2. Explain the role of food (glucose) in both photosynthesis and cellular respiration. 3. Explain how life on Earth depends on the sun. 7.2 Food Stores Chemical Energy Distinguish between kinetic and potential energy. Kinetic Energy: Energy of anything that is in motion Thermal Energy= energy from Moving particles (heat) Potential Energy: Stored energy due to position Explain what chemical energy is and how cells release it from food. Chemical energy= energy stored in the bonds of organic compounds Energy is released by: Cellular respiration Is a chemical reaction Requires oxygen Cells get 40% of energy from compound, 60% is lost as heat. More Info: Remember… Lipids lots of energy Carbs = Sugars= shorterm, small amounts of energy Starches= long term energy Define calories and kilocalories as units of energy. Calories amount of energy required to raise the temperature of 1 gram (g) of water by 1 degree Celsius (°C). Kilocalorie = 1000 calories More Info: “Calories” in conversation is usually a kilocalorie 7.2 Key Terms kinetic energy potential energy thermal energy chemical energy calorie Concept Check 7.2 1. Identify the types of energy you have at the top of a staircase and as you go down the stairs. 2. Explain how your body uses chemical energy during exercise. 3. If a food has 10 kcal of energy, how much could it increase the temperature of 100 g of water? 7.3 ATP Provides Energy for Cellular Work How ATP Packs Energy: ATP = adenosine triphosphate The tail end of 3 P holds the energy When 1 P is removed, energy is released = ADP ATP is recycled by adding a P back to tail ATP and Cellular Work 3 Major types of work Chemical Mechanical Transport ATP Cycle Cycle works super fast Like a rechargeable battery 7.3 Key Term ATP Concept Check 7.3 1. In what way is ATP like a compressed spring? 2. List three main types of cellular work. 3. What is the source of energy for regenerating ATP from ADP? 7.4 Electrons “fall” from food to oxygen during cellular respiration Cellular Respiration Equation Cellular Respiration Aerobic process that releases chemical energy (from organic compounds) Aerobic= requires oxygen Respiration & “Breathing” Breathing supplies cells with O2 and removes CO2 Respiration uses the O2 and gives off CO2 Falling Electrons As electrons fall from electron cloud (energy levels) towards nucleuspotential energy is release Oxygen is a strong electron acceptor (pulls electrons towards its nucleus) Hydrogen and Carbon and weak, lose electrons to Oxygen’s pull Electron Transport Chain Electron Transport Chain= series of atoms that transfer electrons Each transfer releases a small amount of energy Releases energy from large molecule in small, slow steps 7.4 Key Term Aerobic Electron Transport Chain Concept Check 7.4 1. Compare and contrast breathing and cellular respiration. 2. List the reactants and products in cellular respiration. 3. What is meant by the "falling" of electrons to oxygen? How does this process release energy? 4. How does an electron transport chain result in the gradual release of energy stored in glucose? 7.5 Cellular respiration converts energy in food to energy in ATP Structure of the Mitochondria Mitochondria Double membrane organelle Inner membrane has many folds Large surface area provides sites for C.R. Middle contains matrix Cellular Metabolism Metabolism= all cellular processes combined together C.R. , diffusion, photosynthesis, etc. Cellular Respiration consists of a series of chemical reactions (3 Stages) Glycolysis Krebs Cycle Electron Transport Step 1: Glycolysis Occurs outside mitochondria Splits sugar (glucose) Adds 2 ATPs to glucose Energy to start the process Results in: 4 ATP 2 Pyruvic Acid Step 2: Kreb’s Cycle Occurs inside mitochondria Pyruvic acid is converted to Acetyl CoA 1 cycle will produce 1 Acetyle CoA Cycles twice Produces 2 ATPs and 4 CO2 Step 3: Electron Transport Chain Final Stage 2 Parts Electron Transport Chain ATP Synthase- produces the ATP ATP Synthase Protein Structure Converts up to 34 ATPs from each glucose molecule Summary: Cellular Respiration makes ATP Glycolysis= 4 ATP – 2ATP = gain of 2 ATP Krebs = 2 ATP ATP synthase = 34 ATP Total of 38 ATP per glucose molecule 7. 5 Key Terms metabolism glycolysis Krebs cycle ATP synthase 7.5 Concept Check 1. How is the mitochondrion's structure suited to its function? 2. Identify the three stages of cellular respiration, where in the cell each takes place, and how many ATP molecules it produces. 3. Summarize the use and production of ATP in one cycle of cellular respiration. 7.6 Fermentation When does it occur? When O2 is unavailable or supply is insufficient ATP demand is higher that supply produced by Cellular Respiration Fermentation in Muscle Cells Produces ATP through glycolysis Yields 2 ATPs Lactic Acid is a waste product Fermentation by Microorganisms Occurs in anaerobic conditions Produces ATP Alcohol is waste product (instead of lactic acid) Utilized by humans to make: Bread Wine/alcoholic drinks Yogurt Cheese Soy sauce sauerkraut 7.6 Key terms fermentation anaerobic Concept Check 7.6 1. How is fermentation different from cellular respiration? 2. Describe one example of how fermentation in microorganisms produces human foods. 3. What is the waste product of fermentation in your muscle cells?