Glycolysis_Presentation

1. Glycolysis: The Breakdown of
Glucose
An Overview of Energy Generation in
Cells

2. Introduction to Glycolysis
• - Glycolysis is the metabolic pathway that
converts glucose into pyruvate, releasing
energy.
• - Occurs in the cytoplasm of cells.
• - Occurs in both aerobic and anaerobic
conditions.

3. Steps of Glycolysis Overview
• - Divided into Two Phases:
• 1. Energy Investment Phase – ATP
consumption
• 2. Energy Payoff Phase – ATP and NADH
production

4. Step 1 – Glucose Phosphorylation
• - Enzyme: Hexokinase
• - Reaction: Glucose → Glucose-6-phosphate
(G6P)
• - ATP Consumption: 1 ATP used

5. Step 2 – Isomerization
• - Enzyme: Phosphoglucose isomerase
• - Reaction: G6P → Fructose-6-phosphate (F6P)

6. Step 3 – Phosphorylation of F6P
• - Enzyme: Phosphofructokinase-1 (PFK-1)
• - Reaction: F6P → Fructose-1,6-bisphosphate
(F1,6BP)
• - ATP Consumption: 1 ATP used

7. Step 4 – Cleavage of F1,6BP
• - Enzyme: Aldolase
• - Reaction: F1,6BP → DHAP + G3P
• - Only G3P continues; DHAP is converted into
G3P.

8. Step 5 – Isomerization of DHAP
• - Enzyme: Triose phosphate isomerase
• - Reaction: DHAP → G3P

9. Step 6 – Oxidation of G3P
• - Enzyme: Glyceraldehyde-3-phosphate
dehydrogenase
• - Reaction: G3P + NAD⁺ → 1,3-
Bisphosphoglycerate (1,3-BPG) + NADH

10. Step 7 – ATP Generation
• - Enzyme: Phosphoglycerate kinase
• - Reaction: 1,3-BPG → 3-Phosphoglycerate
(3PG)
• - ATP Produced: 2 ATP

11. Step 8 – Rearrangement
• - Enzyme: Phosphoglycerate mutase
• - Reaction: 3PG → 2-Phosphoglycerate (2PG)

12. Step 9 – Dehydration
• - Enzyme: Enolase
• - Reaction: 2PG → Phosphoenolpyruvate (PEP)

13. Step 10 – ATP Production and
Pyruvate Formation
• - Enzyme: Pyruvate kinase
• - Reaction: PEP → Pyruvate + ATP
• - ATP Produced: 2 ATP

14. Energy Yield of Glycolysis
• - Total ATP Used: 2
• - Total ATP Produced: 4
• - Net ATP Gain: 2 ATP
• - Other Products: 2 NADH, 2 Pyruvate

15. Fate of Pyruvate
• - Aerobic: Pyruvate → Acetyl-CoA → Enters
TCA Cycle
• - Anaerobic: Pyruvate → Lactate (in humans)
or Ethanol (in yeast)

16. Regulation of Glycolysis
• - Key Regulatory Enzymes:
• 1. Hexokinase – Inhibited by G6P
• 2. Phosphofructokinase-1 (PFK-1) – Inhibited
by ATP, activated by AMP
• 3. Pyruvate Kinase – Inhibited by ATP

17. Clinical Importance of Glycolysis
• - Role in cancer cells (Warburg effect)
• - Lactic acidosis in anaerobic conditions
• - Glucose metabolism disorders

18. Summary
• - Glycolysis converts glucose → pyruvate
• - Net ATP gain: 2 ATP
• - Generates NADH for further energy
production