Glycolysis is a fundamental metabolic pathway that converts glucose into pyruvate, yielding ATP and NADH for cellular energy. It involves ten enzyme-catalyzed steps, divided into energy investment and payoff phases. This process is crucial for both aerobic and anaerobic respiration, providing energy and metabolic intermediates. Glycolysis also offers insights into the evolutionary history of metabolism, highlighting its ancient origins and essential role in early life forms.
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Glycolysis is a metabolic pathway that breaks down glucose into pyruvate, producing ATP and NADH
Energy Investment Phase
The first phase of glycolysis involves the consumption of ATP to activate glucose and facilitate its breakdown
Energy Payoff Phase
The second phase of glycolysis involves the production of ATP and pyruvate
Glycolysis is a crucial pathway for providing cells with immediate energy and intermediates for further energy-yielding processes
Hexokinase is the enzyme responsible for phosphorylating glucose to glucose-6-phosphate in the first step of glycolysis
PFK-1 is the key regulatory enzyme that catalyzes the phosphorylation of fructose-6-phosphate to fructose-1,6-bisphosphate in the energy investment phase of glycolysis
Pyruvate kinase facilitates the transfer of a phosphate group from phosphoenolpyruvate to ADP, producing ATP and pyruvate in the final step of glycolysis
Glycolysis produces a net gain of two ATP molecules per glucose molecule through substrate-level phosphorylation
Glycolysis also produces two molecules of NADH, which carry high-energy electrons to the electron transport chain for further ATP production
The end products of glycolysis, pyruvate, can be further oxidized in the citric acid cycle under aerobic conditions or converted into lactate or ethanol under anaerobic conditions
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Location of glycolysis in the cell
Occurs in the cytoplasm
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End products of glycolysis
2 pyruvate, 2 ATP, 2 NADH, 2 H+
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Phases of glycolysis
Energy investment phase and energy payoff phase
