Steps involved in Krebs cycle

The Krebs cycle is the second of three phases of cellular respiration, and it involves the oxidation of glucose, fatty acids, and certain amino acids. The energy contained in these molecules is converted into ATP through the oxidation of these molecules. In this step of respiration, a total of 24 ATPs are synthesised. It affects both plants and animals. Anaerobic creatures lack this trait. Aerobic respiration is a process in which cells use oxygen to break down and release energy from basic metabolites. It occurs in the cell’s cytoplasm and mitochondria and produces ATP (Adenosine Triphosphate).

Krebs cycle

The Krebs cycle, also known as the citric acid cycle or the tricarboxylic acid cycle, is one of the most important reaction sequences in biology. Not only are the molecules produced in these reactions responsible for the majority of the energy needs in complex organisms, but they can also be used as building blocks for a variety of important processes, such as the synthesis of fatty acids, steroids, cholesterol, amino acids for protein building, and the purines and pyrimidines used in DNA synthesis.

The Krebs Cycle is a sequence of chemical reactions that use oxygen as part of cellular respiration and are essential in all living cells. The Krebs cycle is the second of four steps that occur during the process of cellular respiration. It’s a crucial stage in the oxidative phosphorylation process.

The Krebs cycle, also known as the tricarboxylic acid cycle (TCA cycle) or citric acid cycle, is a sequence of chemical reactions that use oxygen as part of cellular respiration in all living cells. In eukaryotes, the Krebs cycle occurs in the mitochondria, but in prokaryotes, it occurs in the protoplasm. Each cycle yields one molecule of GTP or ATP, three NADH molecules, and one molecule of FADH2, all of which are required to synthesise ATP for the cell in later cellular respiration activities.

In eukaryotes, the Krebs cycle occurs only within the mitochondrial matrix. Pyruvate is made in the cell’s cytoplasm and then transferred to the mitochondria. Pyruvate is metabolised to acetyl CoA and delivered to the mitochondrial matrix in the intermembrane gap. The innermost section of the mitochondria is the matrix, which is bound by the inner membrane.

Krebs cycle Steps

The Krebs cycle is a major pathway in a bio-complicated organism’s metabolism that serves as a unifying point for a variety of compounds that feed into it at various points.

The Krebs cycle, often known as the Citric acid cycle, is made up of eight steps:

  • Step 1: Pyruvate produces acetyl CoA (a 2-carbon molecule), which interacts with oxaloacetate (a 4-carbon molecule) to generate citrate (a 6-carbon molecule).
  • Step 2: Isocitrate is produced from citrate (an isomer of citrate)
  • Step 3: Isocitrate is converted to alpha-ketoglutarate via oxidation. One molecule of NADH is created, and one molecule of CO2 is released.
  • Step 4: Succinyl CoA, a four-carbon compound, is formed when alpha-ketoglutarate is oxidised. The second molecule of NADH and a second molecule of carbon dioxide are produced.
  • Step 5: Succinate is formed from succinyl CoA. (a 4-carbon molecule). One molecule of GTP is created.
  • Step 6: The succinate is then transformed to fumarate (another 4-carbon molecule). In this process, a molecule of FADHâ?? is formed.
  • Step 7: Malate is generated from fumarate (another 4-carbon molecule).
  • Step 8: The cycle is completed when malate is transformed into oxaloacetate (4 carbon molecules). This step produces the third molecule of NADH.

Functions of Krebs cycle

  • Because it is linked to the generation of electron carriers, the Krebs cycle is an important part of cellular respiration. Because its intermediate products are employed in the manufacture of amino acids, nucleotides, cytochromes, and chlorophylls, the Krebs cycle is also functionally significant.
  • The Krebs cycle is involved in gluconeogenesis, lipogenesis, and amino acid interconversion. In gluconeogenesis, oxaloacetate is transformed into glucose.
  • The Krebs cycle’s succinyl-CoA is utilised to make haemoglobin and myoglobin.

Significance of Krebs cycle

  1. Many organisms will be able to use nutrients other than glucose as a source of energy.
  2. After beta-oxidation, fatty acids or lipids enter the Krebs cycle via acetyl CoA.
  3. The Krebs cycle is involved in gluconeogenesis, lipogenesis, and amino acid interconversion.
  4. Intermediate components of the Krebs Cycle are responsible for the synthesis of amino acids, chlorophyll, and a variety of other chemicals.
  5. Neural harm could result from hereditary abnormalities in Krebs cycle enzymes.

Conclusion

After the eight steps of the Krebs cycle, the four-carbon molecule oxaloacetate, which started the cycle, is regenerated. The Krebs cycle is made up of eight phases that include redox, dehydration, hydration, and decarboxylation reactions. The Krebs cycle produces one GTP or ATP molecule, three NADH molecules, and one FADH2 molecule each revolution. Electrons are transported to NAD+ during the breakdown of pyruvate to create NADH. An acetyl group is transferred to Coenzyme A during the breakdown of pyruvate, resulting in acetyl CoA. In eukaryotes, the Krebs cycle occurs only within the mitochondrial matrix.

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