Difference Between Glycolysis and Krebs Cycle

Difference Between Glycolysis and Krebs Cycle Overview

Glycolysis and the Krebs cycle are two important metabolic pathways in a living cell. Glycolysis breaks down glucose into simpler and smaller molecules, whereas the Krebs cycle oxidizes fatty acids and produces more ATP than glycolysis. In the aerobic Glycolysis pathway, each molecule of glucose produces two molecules of pyruvate (equivalent to two ATP).

In contrast, the Krebs cycle, which also occurs in an aerobic environment, produces 6 ATP molecules for every glucose molecule.  Understanding these distinctions is very important for making informed decisions about the best method of energy production. Large molecules are metabolized into smaller ones, which are collectively known as metabolites. Cells use these metabolites to make new molecules like proteins and carbohydrates. "The Krebs' Cycle" is an essential part of this complex process.

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Difference Between Glycolysis and Krebs Cycle

Glycolysis and the Krebs Cycle differ in their roles in cellular respiration. Glycolysis, the first stage, partially oxidizes glucose, producing pyruvic acid, ATP, NADH, and water. It occurs in the cytoplasm and doesn't need oxygen. The Krebs Cycle, the second stage, fully oxidizes pyruvic acid, yielding carbon dioxide and water. It occurs in the mitochondria and requires oxygen. The detailed difference between glycolysis and krebs cycle are outlined in the table below:

Glycolysis

Glycolysis, the first phase of the citric acid cycle, occurs within the inner mitochondrial membrane. In the presence of oxygen, glucose is broken down into pyruvate and two ATP molecules. Mitochondria use the remaining ATP to generate energy. Glycolysis is a metabolic cycle that involves multiple reactions in the cytoplasm and cytosol, which can lead to glycolytic acid fermentation. In the presence of oxygen, this cycle can produce two ATP molecules for each glucose molecule. In aerobic organisms, glycolysis in the mitochondria of human cells facilitates the catabolic breakdown of food for energy via substrate-level phosphorylation.

Glycolysis is one of the three essential chemical shifts in anabolic metabolism, along with oxidation and reduction. The term "glycolysis" is derived from the combination of "glyco" (cellulose) and "lysis" (breakdown or destruction). The high-energy phosphate bonds formed during glycolysis become available for a variety of energy-intensive cellular processes.  The term "glycolysis" was coined by German biologist Rudolph Auerbach in 1884 during his research into the structure, behavior, and reactions of enzymes involved in this process.

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Krebs Cycle

It is an oxygen-dependent process that takes place within the mitochondria and involves the complete oxidation of the pyruvic acid produced during glycolysis.  This aerobic mechanism involves the complete breakdown of pyruvic acid into CO2 and water. The Krebs cycle, which serves as the second stage of respiration after glycolysis, is distinguished by its cyclical nature.  The Citric Acid Cycle, also known as the Tricarboxylic Acid Cycle, requires oxygen to function.

 The glucose molecule undergoes complete oxidation, producing acetyl CoA, which then enters the citric acid cycle. Acetyl CoA combines with oxaloacetate, a carbon compound, to form a 6-carbon citrate.  During this process, two CO2 molecules are released, oxaloacetate is regenerated, and energy is stored in the forms of ATP, NADH, and FADH.