Bio Chapter 7 Cell Respiration

Chapter 6How Cells Harvest Chemical EnergyIntroduction to Cell Metabolism

Glycolysis

Aerobic Cell Respiration

Anaerobic Cell Respiration

O2CO2BREATHINGLungsCO2O2BloodstreamMuscle cells carrying outCELLULAR RESPIRATIONSugar + O2 ATP + CO2 + H2OBreathing and Cell Respiration are related

GlucoseOxygen gasCarbon dioxideWaterEnergyCellular Respiration uses oxygen and glucose to produce Carbon dioxide, water, and ATP.

Burning glucose in an experimentEnergy released from glucose (as heat and light)100%Energy released from glucose banked in ATPBurning glucose in cellular respirationAbout 40%Gasoline energy converted to movementBurning gasoline in an auto engine25%How efficient is cell respiration?

Loss of hydrogen atomsGlucoseGain of hydrogen atomsEnergyReduction and Oxidation

OILRIG

Oxidation is losing electrons

Reduction is gaining electronsGlucose gives off energy as is is oxidized

Reduction and Oxidation OILRIG Gain or loss of electrons is often in the form of hydrogen. The hydrogen is then passed to a coenzyme such as NAD+

Reduction and Oxidation

What are some common co-enzymes? NAD+ and FADNAD+ + 2 H NADH + H+FAD + 2 H FADH2Remember that H = 2 electrons and 2H+

Reduction and OxidationThese co-enzymes are very important for cell respiration because they transfer high-energy electrons to electron transport systems (ETS).

Reduction and OxidationAs the electrons move from carrier to carrier, energy is released in small quantities.Electron transport system (ETS)

Generation of ATPThere are two ways to generate ATP

Chemiosmosis

Substrate-Level Phosphorylation

Generation of ATPChemiosmosis

Cells use the energy released by falling electrons in the ETS to pump H+ ions across a membrane

Uses the enzyme ATP synthase.

Generation of ATPChemiosmosis

ATP can also be made by transferring phosphate groups from organic molecules to ADPFigure 6.7BsubstrateproductEnzymeAdenosineAdenosineGeneration of ATPSubstrate Level Phosphorylation

General Outline GlucosePyruvic Acid GlycolysisOxygenAerobicNo OxygenAnaerobicTransition ReactionKrebs CycleETS36 ATPFermentation

Glycolysis

Where? The cytosol

What? Breaks down glucose to pyruvic acid

Glycolysis Steps A fuel molecule is energized, using ATP.131GlucoseStep234Glucose-6-phosphateFructose-6-phosphateGlyceraldehyde-3-phosphate (G3P)Step A six-carbon intermediate splits into two three-carbon intermediates.4Step A redox reaction generates NADH.551,3-Diphosphoglyceric acid (2 molecules)6Steps ATP and pyruvic acid are produced.693-Phosphoglyceric acid (2 molecules)72-Phosphoglyceric acid (2 molecules)82-Phosphoglyceric acid (2 molecules)9(2 molecules per glucose molecule)Pyruvic acidFructose-1,6-diphosphateEnergy In: 2 ATPEnergy Out: 4 ATPNET 2 ATP

General Outline of Aerobic Respiration Glycolysis

Krebs CycleElectron Transport SystemTransition Reaction

Transition Reaction

Each pyruvic acid molecule is broken down to form CO2 and a two-carbon acetyl group, which enters the Krebs cycleAcetyl CoAPyruvic Acid


Krebs CycleElectron Transport SystemTransition Reaction

Krebs Cycle

Where? In the Mitochondria

What? Uses Acetyl Co-A to generate ATP, NADH, FADH2, and CO2.

Krebs Cycle


Krebs CycleElectron Transport System

Electron Transport SystemFigure 6.12Intermembrane spaceInner mitochondrial membraneMitochondrial matrixProtein complexElectron carrierElectron flowELECTRON TRANSPORT CHAINATP SYNTHASE

Electron Transport System

Electron Transport SystemFor each glucose molecule that enters cellular respiration, chemiosmosis produces up to 38 ATP molecules

Overview of Aerobic Respiration

FermentationRequires NADH generated by glycolysis.Where do you suppose these reactions take place?Yeast produce carbon dioxide and ethanolMuscle cells produce lactic acidOnly a few ATP are produced per glucose

Fermentation

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Bio Chapter 7 Cell Respiration