Cellular Respiration How we get energy from food

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Cellular Respiration

Cellular RespirationHow we get energy from foodCellular RespirationCellular respiration glucose molecules are broken down to release energyUsed by heterotrophs and autotrophs to gain energy from foodThe food we eat is broken down into simple sugars like glucoseGlucose is broken down to release energy -this energy is used to make ATP

Cellular Respiration getting the energy from foodCellular respiration has to happen in steps otherwise all the energy would be released at once and most would be lost

So it happens in steps and Energy gets released a little at a time

2 Types of Cellular RespirationAerobic - releases energy from food molecules using oxygen

Anaerobic (Fermentation) releases energy from food molecules without oxygenEquation of Cellular Respiration/aerobic/

3 Stages of Cellular RespirationGlycolysis 2 ATP

Krebs cycle 2 ATP

ETC Electron Transport Chain ~ 32 ATP

TOTAL Energy gain for Aerobic Respiration ~ 36 ATP

- Glucose (has 6 carbon atoms) is split into 2 pyruvates (each has 3 carbons)

- 2 ATP molecules are used in this process and 4 are made giving us a net gain of 2 ATP

- From this process you get2 NADH energy storing compound2 ATP 2 Pyruvates used in the next step to release energy

In CytoplasmWhy is Glycolysis important?Only releases 2 ATP but the process happens very fast in the cellSo cells can make thousands of ATP molecules in a few secondsDoesnt need oxygen so it can make energy fast without oxygenKrebs CycleHappens in the matrix of the mitochondriaPyruvate is transformed into acetly-CoA which enters this cycleIn the cycle a set of reactions breaks down acetyl-CoA to:CO2 carbon dioxide (we breathe out)2 ATP what cells use as energy to do workNADH energy storing compoundFAHD2 energy storing compoundFor each turn of the cycle a phosphate is added to ADP to make ATPEach pyruvate causes one turn of the cycle creating one ATPSo 2 molecules of ATP are made for each 2 pyruvates (=1 glucose) that enters the cycle

Electron Transport ChainEnergy is transferred from NADH (from glycolysis) and FADH2 and NADH from the Krebs cycle into the ETCThis step requires oxygen that is why this is aerobic respiration!Electrons move from NADH to FADH2 down the chain on the inside membrane of the mitochondriaJust as in Photosynthesis -as they move ATP is generated - 32 molecules of ATPOxygen is the final electron acceptorAn enzyme adds the electrons to oxygen and hydrogen to make water

FermentationGetting energy from Glucose without oxygenTakes place in the cytoplasmTypes:Alcoholic fermentationLactic acid fermentation

Both types form 2 ATP moleculesAlcoholic FermentationConverts pyruvate and NADH (from glycolysis) into carbon dioxide, ethanol and NAD+Ethanol is an alcohol that is why it is called alcoholic fermentationThis is carried out by yeast bread and beerAnimals cannot carry out this type of fermentationBeer and Bread

Fermentation is your friend

Lactic Acid FermentationConverts pyruvate and NADH (from glycolysis) to lactic acid and NAD+Animals use this in their muscle cellsWhen you exercise a lot breathing cannot give your muscles all the oxygen they needWhen they run out of oxygen they switch to lactic acid fermentation to get energyHave you ever felt the burn while working out, or after an intense workout? That is lactic acid in your muscles

Photosynthesis and Cellular RespirationPhotosynthesis and cellular respiration are related processesThe products for one are the reactants for the otherLook at the formulas:Cellular respiration: