Final answer:
Glycerol is converted to glycerol-3-phosphate, then glyceraldehyde-3-phosphate, and through glycolysis to pyruvic acid, which becomes acetyl CoA. This acetyl CoA enters the Citric Acid Cycle, during which acetyl CoA combines with oxaloacetate to form citrate, which is then oxidized, releasing CO2 and generating ATP, NADH, and FADH2.
Step-by-step explanation:
The conversion of glycerol to citric acid is not a direct process but involves a series of biochemical reactions. Glycerol first enters the glycolysis pathway and is converted to glyceraldehyde-3-phosphate. Following a series of reactions, pyruvic acid is formed which is then converted to acetyl CoA in a transitional phase before entering the Citric Acid Cycle (also known as the Krebs cycle).
Steps in the Citric Acid Cycle for Conversion
- The first reaction involves the combination of the two-carbon acetyl group derived from acetyl CoA with a four-carbon oxaloacetate molecule to form a six-carbon citrate molecule. This is an irreversible condensation reaction that is highly exergonic, denoting a large release of energy.
- Citrate then undergoes an isomerization losing one water molecule and gaining another, converting it into isocitrate.
- The next step of oxidation turns isocitrate into a five-carbon α-ketoglutarate and releases a molecule of CO₂ and two electrons which reduce NAD+ to NADH. This step is also subjected to feedback regulation influenced by the concentration of ATP, NADH, and ADP.
The overall reaction of the citric acid cycle that incorporates one molecule of acetyl-CoA can be summarized as: Acetyl-CoA + 2H₂O + 3NAD+ + Pi + GDP + FAD → 2CO₂ + 3NADH + GTP + CoASH + FADH₂ + 2H+.