Key Idea: What happens during glycolysis?

1 molecule of glucose is transformed into 2 molecules of pyruvic acid and 4 ATP by "investing" 2 ATP molecules to get the process started.

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Net gain: 2 ATP

Total gained so far: 2 ATP​

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Occurs in the cytoplasm​

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Glycolysis

Key Idea: What happens during the Krebs Cycle?

Pyruvic acid (from glycolysis) is broken down into 5 carbon dioxide, 4 NADPH, 2 FADH₂, and 2 ATP

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Net gain: 2 ATP

Total gained so far: 4 ATP​

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Occurs inside the mitochondria​

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The Krebs Cycle

Key Idea: What happens during the electron transport chain

The ETC uses high energy electrons from glycolysis and the Krebs cycle (NADPH and FADH₂ to create ATP.

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Oxygen is used to clean up low energy electrons and H⁺ ions to create water.

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​The mitochondria uses a charge difference and a special enzyme (ATP synthase) to create large amounts of ATP.

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Net gain: 32 ATP

Total gained: 36 ATP

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occurs in the mitochondria​

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Electron Transport Chain (ETC)

Extra Information

The 36 ATP created represents 36% of the total energy in glucose. The rest of the energy is given off as heat.

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The total number of ATP produced in respiration can range from 30-42. 36 is an average.​