Cellular Respiration

• During glycolysis, glucose is broken down into two molecules of pyruvate.
• Cellular respiration occurs in three stages: glycolysis, pyruvate oxidation (in aerobic conditions), and the Krebs cycle/citric acid cycle.
• ATP synthase uses the energy released by protons moving back into the mitochondrial matrix to synthesize ATP.
• The electron transport chain uses the high-energy NADH and FADH2 to produce the majority of ATP through the process of chemiosmosis.
• The electron transport chain is the final step in cellular respiration, where electrons are passed from one carrier molecule to another.
• The Krebs cycle oxidizes the products of glycolysis fully to produce larger amounts of NADH and FADH2 as well as some ATP.
• Glycolysis produces a small amount of ATP and NADH independently of oxygen by breaking down glucose into smaller molecules.
• Anaerobic respiration is a type of cellular respiration that occurs in the absence of oxygen.
• Glycolysis produces a net gain of two molecules of ATP and two molecules of NADH.
• During glycolysis, glucose is broken down into two molecules of pyruvate.
• Pyruvic acid can be converted to lactic acid or ethanol through fermentation.
• The ETC involves three protein complexes embedded in the inner mitochondrial membrane that transfer electrons from NADH to O2 via a series of redox reactions.
• Fermentation occurs when oxygen levels are low, resulting in the production of ATP without using the electron transport chain (ETC).
• Glycolysis takes place in the cytoplasm of cells and does not require oxygen.
• Pyruvate oxidation occurs in the mitochondria and requires oxygen to produce ATP through cellular respiration.
• Glycolysis produces only a small amount of ATP compared to cellular respiration as a whole.
• Pyruvate enters the mitochondria and undergoes decarboxylation to form acetyl CoA.
• Pyruvate oxidation involves the conversion of pyruvate into acetyl CoA, which enters the citric acid cycle.
• Electrons are passed from one carrier to another along the electron transport chain until they reach oxygen, which accepts them as electrons and combines with hydrogen ions to form water.
• The electron transport chain consists of four protein complexes embedded in the inner membrane of the mitochondria.
• Fermentation is an example of anaerobic respiration that does not require oxygen but still breaks down glucose to release energy.
• Pyruvate oxidation converts pyruvate produced during glycolysis into acetyl CoA, which enters the citric acid cycle.
• Proton gradient across the inner membrane drives the production of ATP through chemiosmosis.
• Acetyl CoA combines with oxaloacetic acid to form citrate, which then goes through several steps to regenerate oxaloacetic acid while producing NADH and FADH2.
• In anaerobic conditions, lactic acid fermentation or alcoholic fermentation can occur instead of pyruvate oxidation.
• The Krebs cycle or citric acid cycle also occurs in the mitochondria and produces ATP through cellular respiration.
• In aerobic respiration, the pyruvate produced during glycolysis enters the mitochondria and undergoes further breakdown.
• In anaerobic conditions, lactic acid or ethanol can be formed instead of carbon dioxide.
• Pyruvate can be converted to acetyl CoA, which then enters the citric acid cycle (Krebs cycle).
• Lactic acid production can cause muscle fatigue during exercise when there is insufficient oxygen supply.
• NADH and FADH2 enter the electron transport chain to generate more ATP.
• In fermentation, pyruvate is converted into lactic acid or ethanol without producing carbon dioxide.
• Pyruvate can be converted into lactate or ethanol through fermentation if there is no oxygen present.
• Lactic acid fermentation converts pyruvate into lactate using NAD+ as a coenzyme.
• During the Krebs cycle, acetyl CoA combines with oxaloacetic acid to form citrate, which goes through several reactions to regenerate oxaloacetic acid while producing carbon dioxide, water, reduced coenzymes, and ATP.
• Oxidative phosphorylation requires an input of energy from the electron transport chain (ETC) to drive this process.
• Oxidative phosphorylation generates most of the ATP produced during cellular respiration.
• ATP synthase - This enzyme uses the energy released during oxidative phosphorylation to synthesize ATP.
• ATP synthase uses the proton gradient created during oxidative phosphorylation to synthesize ATP.
• Acetyl CoA combines with oxaloacetic acid to form citrate, initiating the citric acid cycle.