CELLULAR RESPIRATION The process by which mitochondria break down food molecules to produce ATP

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  • CELLULAR RESPIRATIONThe process by which mitochondria break down food molecules to produce ATP

  • There are three stages.GlycolysisCitric acid cycleE-transport chain

  • GLYCOLYSISOverview: series of chemical reactions in the cytoplasm of cells that break down GLUCOSE(C6H12O6) into two-three carbon molecules called pyruvic acid.2 ATP are required to start glycolysisGlycolysis is inefficient because it only produces 4 ATP and has to use two to get going. Leaving a net ATP of 2 for each molecule of glucose broken down.

  • Two Kinds of GlycolysisAnaerobic (W/O O2)ProkaryoticTypically bacteriaFermentation- which produces ethyl alcohol and then breaks down into lactic acid

    Aerobic ( with O2)EukaryoticGlycolysis-4 ATPKrebs Cycle-2 ATPE- transport 32 ATP

    Cellular Respiration: Max Produced 38 ATP/molecule of glucose. Usable is 36

  • Step 12 phosphate groups are attached to glucose(6 carbon sugar)2 ATPs are broken down to supply phosphatesP-C-C-C-C-C-C-P

  • Step 26 Carbon molecule is split into (2)3 Carbon molecules


  • STEP 3

    C-C-C-P(1st PGAL) OxidizedC-C-C-P(2nd PGAL) Oxidized2NAD+(nicotinamide adenine dinucleotide) are reduced (accepts e-),carries it becoming 2NADH + (2H+)NAD is a coenzyme that accepts e- and p+

    2 Phosphates are added to becomeP-C-C-C-P and P-C-C-C-P

  • Step 4Phosphates added in Step I and 3 are removedLeaving 2 molecules of pyruvic Acid C-C-C and C-C-CThe 4 phosphates are combined with molecules of ADP to form 4 ATPS

  • ATP TOTAL SO FAR4 ATP are produced at the end of glycolysis.

    4 ATP 2 ATP= net of 2 ATP going into the citric acid cycle

  • The Citric Acid Cycle or Krebs CycleWhere: MitochondriaWho: All living things When: Always going onWhy: Produce ATP

  • Electron and Proton Carriers FAD(flavin adenine diphosphate)NAD(nicotinamide diphosphate)A total of 3 NADPH molecules are formed and 1 FADH2 molecule is formedThese e-carriers transport energized e- from the citric acid cycle to the electron transport chain in the inner membrane of the mitochondrion

  • STEP 1Pyruvic acid: (Product of glycolysis) (2C2H3OCOOH) reacts with coenzyme A to formAcetyl Coenzyme A orAcetyl CoAC-C-CoA

  • STEP 2C-C-CoA combines with oxaloacetic acid(C4H4O5) and forms Citric AcidA 6 carbon compoundCO2 is released and a H+ is releasedH+ joins with NAD(an enzyme that accepts e- and H+) to form NADH+The 6 Carbon compound is now a 5 carbon compound called ketoglutaric acid

  • STEP 3The Ketoglutaric acid loses a CO2 and a H+ ion and becomes a 4 carbon compound. C-C-C-C (Succinic Acid)The H+ joins with a NAD and forms NADH One ATP forms here

  • STEP 4Succinic Acid Loses a H+ and breaks down into Fumaric acid, another 4 carbon compoundThis H+ hooks up with FAD(flavin adenine dinucleotide) another enzyme to create FADHAnother H+ attaches to FADH and becomes FADH2+

  • Step 5Fumaric Acid breaks into another 4 carbon compound called Malic acidNADH and FADH are used to regenerate Oxaloacetic acid and the cycle begins again

  • Part 3 : The Electron Transport ChainWhere: inner mitochondrion membraneNADH and FADH2 Pass energized e- from protein to protein within the membrane.Releasing energy along the waySome of that energy is used to create ATP and some is used to pump H+ ions into the center of the mitochondrionInside the membrane is + charged and outside is - charged

  • Electron Transport ContinuedThe inner membrane forms ATP from this electrochemical gradient across the mitochondrial membrane. The final electron acceptor is Oxygen Which reacts with 4 H+ to form 2 H2OsThe e- transport chain produces 32 ATPs32 ATP + 2 ATP in Krebs + 2 from glycolysis = 36 total ATPs produced in cellular respiration

  • Comparison of photosynthesis and Cellular RespirationPhotosynthesisFood accumulatedEnergy from sun stored in glucoseCarbon dioxide taken inOxygen given offProduces glucose from PGALGoes only in lightOccurs in the presence of chlorophyllCellular RespirationFood broken downEnergy of glucose is releasedCO2 given offOxygen taken inProduces CO2 and H2OGoes on all day and nightOccurs in living cells


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