Various chemical processes take place all around us. But, despite our lack of interest, we are once again confronted with two such common phenomena: glycolysis and fermentation. The process starts in the living organisms’ cells. They are unmistakably dissimilar, but how dissimilar are they? This is something we’ll look into in this article.
Glycolysis vs Fermentation
The main difference between glycolysis and fermentation is that glycolysis may or may not require oxygen, whereas fermentation occurs without it. Glycolysis is the first step in the production of the energy-storing molecule ATP, and once it is started, it can proceed in one of two ways: with or without oxygen. Fermentation is the result of a path devoid of oxygen.
Glycolysis is the first step in the process of cellular respiration. The process begins with the breakdown of glucose, a six-carbon molecule that is split into two molecules with three carbon atoms each. The process can occur both in the presence of oxygen and in the absence of oxygen.
On the other hand, fermentation is an anaerobic chemical reaction that occurs as part of cellular respiration. Anaerobic respiration is another term for fermentation. The reaction takes place in the cytoplasm of eukaryotic cells. This mode of reaction is also less efficient than the first because it occurs when oxygen is scarce.
Comparison Table Between Glycolysis and Fermentation
| Parameters of comparison | Glycolysis | Fermentation |
| Does it take in presence of oxygen? | Yes | No |
| Occurrence | Mitochondria | Cytoplasm |
| How many ATP molecules does it produce? | 4 ATP molecules | 2 ATP molecules |
| Chemical conversion | Glucose to pyruvate | Pyruvate to lactic acid and alcohol |
| End products | 2 pyruvate molecules, 4 ATP molecules, and two NADH. | CO2, ethanol, and energy. |
What is Glycolysis?
Food is used as fuel by an organism, and the food is converted into fuel through a series of chemical reactions. We’re talking about glycolysis, the first stage of cellular respiration. It aids in the formation of ATP, or Adenosine Triphosphate, which is a type of energy molecule. The breakdown of the glucose molecule is the first step in the glycolysis process. Six carbon atoms make up a glucose molecule. The procedure can be performed in the presence or absence of oxygen. In the presence of oxygen, glycolysis progresses to Kreb’s cycle. The citric acid cycle is followed by the electron transfer change step in the Krebs cycle. ATP is initially produced in this step.
Though the process’ main goal is to produce energy (ATPs), it begins by breaking down glucose with the help of two ATP molecules. The glucose is split into two molecules, each with three carbons. These two-three carbons, or phosphoglyceraldehyde, are then converted into pyruvate, a three-carbon molecule. It’s also worth noting that each phosphoglyceraldehyde generates two ATP molecules, for a total of four ATP molecules and NADH. In the ETC phase, NADH aids in the production of ATPs. The most important thing to remember is that glucose is converted into pyruvate molecules.
What is Fermentation?
In contrast, fermentation is an anaerobic chemical reaction that takes place during cellular respiration. Anaerobic respiration is another name for fermentation. The reaction takes place in the cytoplasm of eukaryotic cells. This mode of reaction is less efficient than the first because it occurs when oxygen is scarce. Fermentation can take two forms: one occurs in plants and yeast, and the other occurs in animals. It’s worth noting that yeasts are single-celled organisms. Glucose is the fundamental molecule for both types; as previously stated, it is a six-carbon atom molecule.
What distinguishes the two types of plants, yeast, and animals are their end products. In plants and yeasts, it produces ethanol, carbon dioxide, and energy. Exothermic processes are those that release energy, which is why respiration is called an exothermic process. Animals, on the other hand, produce lactic acid and energy. In comparison to fermentation, which is an aerobic respiratory process, glycolysis releases a lot more energy. Thus, four ATP molecules are produced during glycolysis, whereas only two ATP molecules can be produced during fermentation. The fermentation lacks oxidative phosphorylation, which occurs in the absence of oxygen. In contrast to glycolysis, fermentation does not allow for the Krebs cycle or the electron transport phase.
Main Differences Between Glycolysis and Fermentation
- Glycolysis can either be in presence of air or absence of air but fermentation takes place only in absence of air.
- Glycolysis produces more energy as compared to fermentation.
- Glycolysis gives the end product pyruvate whereas fermentation produces acid or alcohol and energy.
- The final stages of glycolysis (aerobic) take place in the mitochondria of eukaryotic cells, whereas fermentation takes place in the cytoplasm.
- Carbon dioxide is not produced by glycolysis, but it is produced by fermentation in plants and yeasts.
Conclusion
The first step in the glycolysis process is the breakdown of the glucose molecule. Glycolysis progresses to Kreb’s cycle in the presence of oxygen. In this step, ATP is created for the first time. The process begins by breaking down glucose with the help of two ATP molecules, even though the main goal is to produce energy (ATPs). NADH assists in the production of ATPs during the ETC phase. The main thing to keep in mind is that glucose is converted into pyruvate molecules.
Fermentation, on the other hand, is an anaerobic chemical reaction that occurs during cellular respiration. Fermentation can occur in two ways: one in plants and yeast, and another in animals. The end products of the two types of plants, yeast, and animals are what distinguish them. It produces ethanol, carbon dioxide, and energy in plants and yeasts. Glycolysis releases a lot more energy than fermentation, which is an aerobic respiratory process.
Glycolysis and fermentation differ primarily in that glycolysis may or may not require oxygen, whereas fermentation does not. Glycolysis is the first step in the production of the energy-storing molecule ATP, and it can go one of two ways once it’s started: with or without oxygen. Fermentation is the result of an oxygen-free path.
References
- https://cdnsciencepub.com/doi/pdf/10.1139/cjms51-008
- https://www.tandfonline.com/doi/abs/10.1007/s10310-004-0140-9