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Cellular respirationOverviewC6H12O6+ 6O2 6CO2+ 6H2O + energy (36 ATP)Opposite of photosynthesisEnergy being released from food in the presence of oxygen3 stages of cellular respirationGlycolysis No oxygen neededKrebs cycle Oxygen neededElectron transport chain (ETC) Oxygen neededPresence of oxygenIf reaction takes place using oxygen, it is said to be aerobic (Krebs and ETC)If reaction takes place without oxygen, it is said to be anaerobic (Glycolysis)Energy in foodA calorie is the amount of energy needed to raise the temperature of 1 gram of water 1C1 Calorie on a label = 1000 calorieReally a kilocalorieCarbohydrates and proteins 4 Cal / gramFats 9 Cal / gram

Glycolysis (splitting of sugar)1st step in cellular respirationGlucose (6C) splits into 2 pyruvic acids (3C)Occurs in the cytoplasmDoes NOT require oxygenSteps of glycolysis2 ATP 2 ADP energy released is used to split glucoseTransfer of electrons (H+ ions) to 2 NAD+ to make 2 NADH4 ADP 4 ATP

Summary2 ATP 2 ADP, 2 NAD+ 2 NADH, 4 ADP 4 ATP, 1 glucose 2 pyruvic acidsOverall products2 pyruvic acids, 2 NADH, 2 ATPAdvantages of glycolysisOccurs very quicklyDoes not require oxygenKrebs cycle2nd step of cellular respiration Takes place in the matrix of the mitochondriaRequires oxygen

Krebs cycle cont.Steps2 pyruvic acids break down into 2 acetic acids. 2 CO2 are released 2 NAD+ 2 NADHAcetic acid joins with Coenzyme A acetyl-CoAAcetyl group is transferred to a 4C molecule to make Citric acid (6C) starts Krebs cycle (AKA citric acid cycle)6C molecule gradually breaks down into a 4C molecule 2 CO2 is released Electrons are transferred to 4 NADHElectrons are transferred to 1 FADH21 ATP is formed

To ETC

Summary of Krebs8 NADH2 ATP2 FADH26 CO2 released

Glycolysis & Krebs10 NADH2 FADH24 ATPElectron transport Chain3rd and final step of cellular respirationTakes place in the inner membrane of mitochondria in eukaryotes and in the cell membrane of prokaryotes.Requires oxygenETC CONT.High energy electrons from glycolysis & Krebs are transported to the ETC by NADH &FADH2Electrons pass from carriers through the ETC to oxygen to form waterAs e- pass through ETC they lose energyEnergy lost from e-, is used to pump H+ across the membraneWith a high conc. of H+ outside of the membrane and a low conc. Inside the membrane H+ pass through ATP synthaseATP synthase rotates and adds a phosphate group to ADP to make ATP. Electron transport chain

Atp formationFor every 2 electrons that pass through the ETC, enough energy is released to produce 3 molecules of ATP.32 ATP are produced by ETC

Cellular respiration summary of ATPGlycolysis + Krebs + ETC 2 + 2 + 32 = 36 ATP / glucoseC6H12O6 + 6 O2 36 ATP + 6 CO2 + 6 H2O

FermentationProduces ATP from food without the use of oxygenGlycolysis produces ATP and NADH, but it cant continue if there is no NAD+Fermentation returns NADH to NAD+Glycolysis and fermentation are called anaerobic respiration2 forms of fermentationAlcoholic fermentationLactic acid fermentationAlcoholic fermentationYeast and other microorganismsProduce ethyl alcohol and CO2Pyruvic acid + NADH ethyl alcohol + CO2 + NAD+Used to make alcoholic beverages and to make bread rise

Lactic acid fermentationMost organismsPyruvic acid + NADH Lactic acid + NAD+Used to produce food Gives sour tasteCheese, yogurt, buttermilk, sour cream, pickles, sauerkrautHumans are lactic acid fermentersMuscle cells are best adapted for lactic acid fermentationTypes of fermentation

Energy supplyThree sources of ATPATP already in the musclesATP make through lactic acid fermentationATP made from cellular respiration

Short term energyMuscles only contain enough ATP for a few seconds of intense activityAfter that ATP is produced by lactic acid fermentationMakes enough ATP for about 90 seconds of activityLactic acid builds up in muscles and takes excess oxygen to get rid of acidIn quick bursts of energy, the body uses ATP already in the body along with ATP made through lactic acid fermentation. Long term energyFor activity lasting longer than 90 seconds, cellular respiration is the only way to continue producing ATPGlycogen in the muscles supplies energy for 15 20 minutes.After that other stored molecules (such as fats) are broken down.SoundJay.com Sound Effectsnull10272.0