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Energy and the Cell. Energy:. All living things must obtain and use energy E Energy cannot be created nor destroyed Energy can be transformed. Energy (cont). The only constant source of energy for the earth is the sun
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Energy: • All living things must obtain and use energy E • Energy cannot be created nor destroyed • Energy can be transformed
Energy (cont). • The only constant source of energy for the earth is the sun • Almost all living cells depend on the sun for energy either directly or indirectly.
Glucose and the cell: • C6H12O6 • Glucose is the final product of photosynthesis • Glucose is used by most living cells as the primary food molecule.
Chemical Reaction of Photosynthesis: 6CO2 + 6H2O + LIGHT C6H12O6 + 6O2
Photosynthetic Organisms: • Autotrophs or Producers convert the E in sunlight to chemical E in food (sugar)
Autotrophs: • Examples of autotrophs include: Plants, algae, and some bacteria. b/g algae algae Plant
Autotroph • Auto ---- “self” • Troph ---- “feeder” • Autotrophs produce their own food, and are the basis for the food chain.
Photosynthesis: • Stores light E in the chem bonds of sugar: 6CO2 + 6H2O + LIGHT C6H12O6 + 6O2
Photosynthesis • The in the reaction represents many intermediate steps. • Two main categories: • lightreactions- trapping E from sunlight • darkreactions- storing E in sugars
Chlorophyll • Chlorophyll- the material that allows plants to trap the E from sunlight. • Chlorophyll absorbs blue and UV light, and red light. • Chlorophyll reflects green, and most yellow light
Photosynthesis • Takes place in the chloroplasts • Light Reactions occur in the thylakoids • Dark Reactions occur in the stroma
H2O CO2 Light Dark Reactions Light Reactions O2 Glucose
Light Reactions • Process by which the energy from sunlight is captured by chlorophyll. (in the thylakoid membrane) • O2 is given off as a byproduct
Dark Reactions (aka Calvin Cycle) • Process by which energy from the light reactions and CO2 are used to build glucose molecules. • C6H12O6
THE GOAL: TO PRODUCE ATPFOR USE WITHIN THE CELL!
Energy Storing Compounds • Starches, sugars, even gasoline are E-storing compounds • Principle E-storing compound for the cell is ATP
ATP • “Adenosine Triphosphate“ • Made up of • Adenine (nitrogenous base) • Ribose (5-C sugar) • Three phosphates
ATP • Energy is stored when phosphates are added • ADP + P (+ energy) ATP • Energy is released when phosphates are removed • ATP ADP + P (+ energy)
Cellular Respiration • Catabolism is breaking down chemicals into their parts • Cellular Respiration is catabolism that releases energy for use in the cell (ATP) • Can be Aerobic (with O2), or Anaerobic (without O2)
Aerobic Respiration C6H12O6+O2CO2+H20 + (E) Energy is released from the sugar in the form of ATP for use within the cell.
Aerobic Respiration • Requires the presence of O2 • Extremely efficient • produces approx. 36 ATP per glucose molecule
Steps of Aerobic Respiration: 1. Glycolysis 2. Krebs Cycle 3. Electron Transport Chain (ETC)
Glycolysis • Takes place in the cytoplasm • “Glyco” meaning “sugar” • “lysis” meaning “to break” • Glucose molecules are broken down into pyruvic acid which will then enter the Krebs cycle
Krebs Cycle
Krebs Cycle • Takes place in the matrix of the mitochondria • Pyruvic acid from glycolysis is broken down to produce high energy molecules(NADH and FADH2 - which go to the ETC) • CO2 is given off as a byproduct
Mitochondrion Matrix
Electron Transport Chain
Electron Transport Chain (ETC) • Like the Krebs Cycle, ETC takes place in the mitochondria • Specifically, the ETC occurs in the Inner Membrane and the Intermembrane Space of the mitochondria.
Mitochondrion Inner Membrane
Mitochondrion Outer Membrane
Mitochondrion Intermembrane Space
ETC cont. • Folds and projections called crista (cristae) in the inner membrane of the mitochondria increase the surface area available for the reactions.
Mitochondrion Crista
ETC cont. • Most of the ATP from Aerobic Respiration is generated by the Electron Transport Chain • This series of reactions converts the high energy molecules from the Krebs Cycle into ATP for use in the cell • Oxygen is required
Anaerobic Respiration
Anaerobic Respiration • Takes place when O2 is not present. • Far less efficient than aerobic respiration • produces approx. 2 ATP per glucose molecule