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CELLULAR RESPIRATION. How Cells Obtain Energy To Sustain Life. ENERGETICS. Life Requires Energy!. ORIGIN OF ENERGY. Nearly all energy for life on earth comes from sunlight Energy in sunlight is captured by photosynthesis. THE BIG PICTURE. CELLULAR RESPIRATION.
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CELLULAR RESPIRATION How Cells Obtain Energy To Sustain Life
ENERGETICS Life Requires Energy!
ORIGIN OF ENERGY • Nearly all energy for life on earth comes from sunlight • Energy in sunlight is captured by photosynthesis
CELLULAR RESPIRATION • The physical act of breathing and the process of cellular respiration share reactants and products
REQUIREMENTS OF RESPIRATION • Cellular Respiration Requires:
STARTING MATERIAL FOR CELLULAR RESPIRATION H O 1 C 6 CH2OH 2 H OH C 5 H H C O 3 HO C H 1 4 H C C 4 OH OH H H C HO OH 2 3 C C 5 H C OH H OH 6 H C OH H
STARTING MATERIAL Glucose: • All cells must break C-bonds in glucose to release energy • Energy stored in bonds
MANY REACTIONS REQUIRE AN INPUT OF ENERGY • Many Reactions in Cells are Not Spontaneous
MANY REACTIONS REQUIRE AN INPUT OF ENERGY HYDROLYSIS OF ATP RELEASES ENERGY Pi P P P P P H2O Energy Water Inorganic phosphate + ADP + + ATP 7.3 kcal/molATP • Bonds in ATP hold significant amount of energy!
CATYLSTS INCREASE RATES OF REACTION • Even with enough energy, there is no guarantee rxns will proceed at a suitable speed
CATYLSTS INCREASE RATES OF REACTION Lock & Key Model: • Substrate fits into enzyme like a key fits into a lock • Enzyme then catalyzes the chemical reaction and releases the products
CATYLSTS INCREASE RATES OF REACTION Substrate Enzyme LOCK & KEY MODEL OF ENZYME AND SUBSTRATE Substrate (Key) A B —C A—B C A B C Shape change Enzyme (Lock)
CATYLSTS INCREASE RATES OF REACTION Enzymes:
MOLECULAR HELPERS Two Molecules Help Cell Respiration Proceed: • Carry (and store) high energy electrons • Later transfer energy to other molecules
OXIDATION-REDUCTION REACTIONS OIL RIG Oxidation = Reduction =
CELLULAR RESPIRATION IS A SERIES OF REDOX REACTIONS In Cellular Respiration: • Oxidation of C in glucose tied to reduction of other • molecules (ex:NAD+)