Aerobic vs Anaerobic Glycolysis – Difference and Comparison

What is Aerobic Glycolysis?

Aerobic glycolysis is a glycolytic process that takes place in the presence of oxygen in the cytosol. As a result, it causes aerobic respiration, which is a form of cellular respiration that occurs in the presence of oxygen. The Krebs cycle and oxidative phosphorylation are the two successive phases of aerobic respiration. Aerobic glycolysis exclusively occurs only in eukaryotic cells.

Pyruvate, the final product of aerobic glycolysis, is transported to mitochondria to initiate the citric acid cycle. As an outcome, 34 Adenosine triphosphate molecules, water, and CO2 are the end products of aerobic glycolysis.

Aerobic glycolysis is also known as the Warburg Effect, which happens when C6H12O6 is turned to lactate in the presence of oxygen. When O2 is insufficient or cells are conducting aerobic glycolysis, NADH transforms pyruvate to lactate instead of reoxidizing it in mitochondria via oxidative phosphorylation. Ultimately, this lowers the overall ATP production in aerobic respiration. The clinical importance of aerobic glycolysis, on the other hand, arises within cancer stem cells in a tumour. As a result, excessive aerobic glycolysis has been linked to deadly cancer.

What is Anaerobic Glycolysis?

When there is no oxygen available, anaerobic glycolysis normally occurs. Anaerobic respiration happens as a result of this. Ethanol fermentation and lactic acid fermentation are two types of anaerobic respiration. Ethanol fermentation is mostly carried out in yeast, whereas lactic acid fermentation is carried out in mammals. Furthermore, in bacteria, lactate is substituted by other compounds such as propionate.

in ethanol fermentation, pyruvate, the final product of glycolysis, is converted into C2H4O by pyruvate decarboxylase, releasing CO2. The enzyme alcohol dehydrogenase then transforms acetaldehyde into ethanol. Lactic acid fermentation happens in muscle cells in the absence of enough oxygen by turning pyruvate into lactate. Anaerobic glycolysis may happen in both eukaryotic and prokaryotic cells, and it can happen in the cytosol or the cytoplasm.

Lactate is produced during anaerobic glycolysis, which lowers the pH and inactivates the enzymes. Anaerobic glycolysis is assumed to be the predominant source of energy in earlier species before oxygen was abundant in nature, and hence represents a more primitive mode of energy generation in cells.

Difference Between Aerobic Glycolysis and Anaerobic Glycolysis

1. Aerobic glycolysis occurs when there is oxygen, whereas anaerobic glycolysis occurs when there is no oxygen.
2.  Aerobic glycolysis results in a substantially more efficient ATP generation pathway, producing 32 ATPs per glucose molecule, whereas anaerobic glycolysis results in a less efficient ATP production pathway, producing 2 ATPs per glucose molecule.
3. Aerobic glycolysis occurs predominantly within eukaryotic cells, whereas anaerobic glycolysis occurs in both prokaryotic and eukaryotic cells.
4. Anaerobic glycolysis produces lactate as the end product, which can be damaging to cells, whereas aerobic glycolysis produces water and carbon dioxide, which are not hazardous to cells.
5. Aerobic glycolysis continues inside the mitochondria, whereas anaerobic glycolysis continues in the cytoplasm.
6.  Aerobic glycolysis involves the Krebs cycle as well as oxidative phosphorylation, whereas anaerobic glycolysis involves either ethanol fermentation or lactic acid fermentation.
7. Aerobic glycolysis converts the produced pyruvate to acetyl coenzyme A, whereas anaerobic glycolysis converts it to lactate or acetaldehyde.

Comparison Between Aerobic Glycolysis and Anaerobic Glycolysis

References

1. https://muse.jhu.edu/article/403868/summary
2. https://cancerres.aacrjournals.org/content/10/2/77.short