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Key Words. anaerobic process : does not require O 2 to occur aerobic process : requires O 2 to occur glycolysis : biochemical pathway that breaks down glucose into pyruvic acid pyruvic acid : 3-carbon molecule made from glucose during glycolysis NADH : an energy-carrying molecule
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Key Words • anaerobic process: does not require O2 to occur • aerobic process: requires O2 to occur • glycolysis: biochemical pathway that breaks down glucose into pyruvic acid • pyruvic acid: 3-carbon molecule made from glucose during glycolysis • NADH: an energy-carrying molecule • fermentation: another pathway that converts glucose into ATP
What is Cellular Respiration? • how cells receive energy from nutrients • breaks down organic molecules (ex: sugars) into ATP • occurs in mitochondria (therefore, this occurs in both plants AND animals)
Equation for Cellular Respiration ------> C6H12O0+ 6 O2 6 CO2 + 6 H20 (glucose) (oxygen) (carbon dioxide) (water) REACTANTS (starting materials) PRODUCTS (end result)
Stages of Cellular Respiration Stage 1 – GLYCOLYSIS • uses glucose made during photosynthesis • breaks down glucose into 2 molecules of pyruvic acid • in the process, a small amount of ATP and NADH is made What comes next depends on one factor… the presence of OXYGEN.
Stage 2 NO, there is not O2 present: YES, there is O2 present: Stage 2 = AEROBIC RESPIRATION Has two stages: Krebs Cycle Electron Transport Chain (ETC) • Stage 2 = FERMENTATION • creates lactic acid or ethyl alcohol • these can be converted to ATP • inefficient process (wastes energy)
Krebs Cycle • Picks up where glycolysis left off. • Takes 2 molecules of pyruvic acid (made in glycolysis), converts them into various molecules over several cycles • involves enzymes such as Co-enzyme A • Pyruvic acid is converted into Acetyl CoA via enzymes. When this occurs, CO2 is produced. • End result: 2 molecules of ATP made in each cycle • One glucose molecule will fuel two Krebs Cycle (therefore, 1 glucose -> 4 ATP)
Electron Transport Chain • similar to photosynthesis • occurs on the inner membrane of mitochondria • transfers electrons throughout several molecules, building up energy • when enough energy is built up (from NADH and FADH2), ATP is created • NADH and FADH2 created during the Krebs Cycle • chemiosmosis = production of ATP via chemicals