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Cellular Respiration. WE NEED ENERGY!. Process where the mitochondria breaks down food molecule to produce ATP. What is it?. Cellular Respiration. Aerobic Respiration. Anaerobic Respiration. Requires oxygen to occur. Occurs in the absence of oxygen.
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Cellular Respiration WE NEED ENERGY!
Process where the mitochondria breaks down food molecule to produce ATP What is it?
Cellular Respiration Aerobic Respiration Anaerobic Respiration Requires oxygen to occur Occurs in the absence of oxygen 3 Steps: - Glycolysis - Krebs - ETC Alcohol Fermentation Lactic Acid Fermentation
The Phases of Respiration • We will talk about each 1 in detail… • Glycolysis • Formation of Acetyl-CoA • Citric Acid Cycle (AKA Krebs Cycle) • Electron Transport Chain
Series of chemical reactions in the cytoplasm that break down glucose into 2 molecules of pyruvic acid In order for glycolysis to occur requires 2 ATPs The end result 4 ATPS are produced NOT A VERY EFFECTIVE PROCESS! NAD+ (electron carrier) accepts 2 electrons to form 2 NADH + 2H+ The products: 2 molecules of pyruvic acid 2 NADH 2 ATPs (WHY?) Glycolysis
Formation of Acetyl-CoA • This is an intermediate step • Following glycolysis, pyruvic acid is transported to the mitochondria and undergoes a series of reactions • The Results of these reactions: • Pyruvic acid (3 carbons) is split apart gives off CO2. • Remaining 2 carbon molecule combines with Coenzyme A to produce Acetyl-CoA • Produces another molecule of NADH and H+
Also called the Krebs Cycles Series of chemical reactions (similar to the Calvin Cycle). The molecule used in the first reaction is also the end product The products for every turn (must turn 2 times): 1 ATP x 2 = 2ATPs 2 CO2 x 2 = 4 CO2 3 NADH + 3H+ x 2 = 6NADH + 6H+ 1FADH2 x 2 = 2FADH2 Citric Acid Cycle electron carriers
Electron Transport Chain • Occurs in the inner membrane of the mitochondria
Final electron acceptor = OXYGEN Reacts with 4 H+ ions and 4 electrons to produce 2 H2O Without oxygen, the proteins in the transport chain cannot pass electrons The Products: 32 ATP 2 H2O Electron Transport Chain
Aerobic Respiration Products • Carbon Dioxide • Water • 36 ATPs
Anaerobic Respiration • Recall: occurs without oxygen • Also referred to as fermentation • There are certain instances (ie: during heavy exercise), when your cells are without oxygen for short periods of time • Fermentation follows glycolysis to produce ATP until oxygen is available again
Lactic Acid Fermentation • Supplies energy while oxygen is scarce • 2 molecules of pyruvic acid produced in glycolysis use NADH to form 2 molecules of lactic acid • Lactic acid is transferred to the muscles • Builds up as your muscles fatigue • Recall 2 molecules of ATP are produced during glycolysis. As a result, lactic acid fermentation also produces 2 ATPs!
Alcohol Fermentation • Used by yeast cells and some bacteria to produce CO2 and ethyl alcohol • Often occurs during baking: • Bread making: yeast cells produce CO2 bubbles in the dough as it bakes • The bubble pockets are left to lighten the bread