Cellular Respiration 9.2 The Process of Cellular Respiration

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Cellular Respiration

Cellular Respiration9.2 The Process of Cellular RespirationTHINK ABOUT ITFood burns! How does a living cell extract the energy stored in food without setting a fire or blowing things up? THINK ABOUT ITMitochondria are where Cellular Respiration takes place.

A microscope in which a beam of electrons is transmitted through an ultra thin specimen.An image is formed from the interaction of electrons transmitted through the specimen. The image is magnified and focused on an imaging device. 3Energy Totals for Cellular RespirationIn the presence of oxygen, the complete breakdown of glucose produces 36 ATP molecules.

This represents about 36 percent of the total energy of glucose. The remaining 64 percent is released as heat.

Three Stages:GlycolysisKreb CycleElectron Transport ChainGlycolysisGlucose is broken down into 2 molecules of the 3-carbon molecule pyruvic acid.

Pyruvic acid is a reactant in the Krebs cycle.

ATP and NADH are produced as part of the process.

ATP ProductionGlycolysis requires 2 ATP molecules to get started.

4 ATP are produced during the reactions.

The net total from Glycolysis: 2 ATP

NADH ProductionDuring glycolysis, the electron carrier NAD+ accepts a pair of high-energy electrons and becomes NADH.

NADH ProductionNADH carries the high-energy electrons to the electron transport chain, where they can be used to produce more ATP.

2 NADH molecules are produced for every molecule of glucose that enters glycolysis.

The Krebs CycleStep 1: Pyruvic acid to Acetyl-CoAPyruvic acid from glycolysis enters the matrix to form Acetyl-CoA.

Matrix, the innermost compartment of the mitochondrion.

Step 1: Pyruvic acid to Acetyl-CoANAD+ accepts 2 high-energy electrons to form NADH.

One molecule of CO2 is also produced.

Step 2: Citric Acid ProductionAcetyl-CoA reacts to produce Citric acid.

Step 3: Cycling & Energy ExtractionCitric acid goes through several reactions, finally forming a 4-carbon oxaloacetate which begins the cycle again.

Two molecules of CO2 are released.

Step 3: Cycling & Energy ExtractionEnergy released by the breaking and rearranging of carbon bonds is captured in ATP, NADH, and FADH2.

NADH and FADH2 move to the Electron Transport Chain.

ATP is used to power cell activities.

Energy ExtractionEach molecule of glucose results in 2 molecules of pyruvic acid. Each pyruvic acid turns through the Kreb Cycle.

For one glucose molecule, 6 CO2, 2 ATP, 8 NADH, and 2 FADH2 molecules are produced. Review Cellular RespirationGlycolysis, Krebs Cycle, ETC2 ATP, 2 ATP, 32 ATPCytoplasm, mitochondria, mitochondria

With oxygen, aerobicGlycolysisWhat happens during the process of glycolysis?

During glycolysis, 1 molecule of glucose, a 6-carbon compound, is transformed into 2 molecules of pyruvic acid, a 3-carbon compound.

The Advantages of GlycolysisGlycolysis produces ATP very fast, which is an advantage when the energy demands of the cell suddenly increase.

Glycolysis does not require oxygen, so it can quickly supply energy to cells when oxygen is unavailable.The Krebs CycleWhat happens during the Krebs cycle?

During the Krebs cycle, pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions.

Electron Transport and ATP SynthesisHow does the electron transport chain use high-energy electrons from glycolysis and the Krebs cycle?

The electron transport chain uses the high-energy electrons from glycolysis and the Krebs cycle to convert ADP into ATP.