• Oldest reaction

• Prokaryotes and Eukaryotes

• does not require oxygen

• in cytosol

• 10 reactions that oxidized glucose into 2 pyruvates

• Energy is released is used to synthesize ATP and NADH

2 Phases

Energy Investment

• 5 steps

• Consumes 2 ATP

• ENDERGONIC

Energy Payoff

• 5 steps

• Yields 4 ATP and 2 NADH (gonna be worth 6 ATP later)

• EXERGONIC

Efficiency of Glycolysis:

• 1 mole of ATP stores 31 kJ of energy

• Each mole of glucose yields 2 moles of ATP from glycolysis (62 kJ)

• 1 mole of glucose, when completely oxidized, releases 2870 kJ

• Efficiency = 62kJ/2870kJ x 100% = 2.2%

• The pyruvates have lower energy than the one glucose due to oxidization

• Remaining energy is stored in pyruvate and NADH, or lost as heat.

• Though the percentage return for glycolysis is low, some organisms use glycolysis as their primary source of energy. For aerobic organisms, however, this is just the beginning process.