Cellular Respiration Part II College Prep Natural Science Flora 2008

Food Into Energy Cellular Respiration is the process that all cells use to break down glucose to yield the energy that cells need to function……. C.R. can occur with or without oxygen w/out oxygen is called anaerobic respiration w/oxygen is called aerobic respiration

Aerobic Respiration Glycolysis Krebs Cycle Electron Transport Chain The result/goal of all of these processes is to produce ATP which gives the cells energy

Glycolysis Process by which a 6-carbon glucose molecule is broken down into two 3-carbon pyruvate molecules Occurs in the cytoplasm Small amounts of ATP and NADH are produced ATP – energy transport molecule NADH is a hydrogen and energy carrier ** If oxygen is present, then pyruvate enters the Krebs Cycle

Krebs Cycle Begins with pyruvate and is transported to the mitochondria CO2 is released out of the pyruvate and more ATP and NADH are produced CO2 is released from the cell as gas Since glycolysis produced two pyruvate molecules, two turns of the Krebs cycle are required to break down both pyruvate molecules

Electron Transport System Uses NADH from the previous stages and these molecules carry hydrogen and energy “ETS” has a series of electron carrier molecules embedded in the inner membrane of the mitochondria As the electrons move from one carrier to the next they release energy With the energy they release, some of the protons are pumped across the membrane creating a concentration gradient

Cont. “ETS” As the protons diffuse back across the membrane they pass through and enzyme complex that synthesizes/makes ATP The electrons and protons then join oxygen gas to form water This is the greatest ATP production process of all the three stages

Summary of Aerobic Respiration Sugar + Oxygen → Carbon Dioxide + water + ATP (energy)

Anaerobic Respiration Glycolysis takes place Pyruvate is converted into other molecules and the Krebs cycle and the electron transport system do not occur - ** This is called fermentation Does not produce near as much energy as aerobic respiration, but gets some animals by when they need energy! Like you and me!!

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