Respiration

Understanding Respiration

  • Respiration is the process by which organisms convert biochemical energy from nutrients into adenosine triphosphate (ATP), releasing waste products.
  • This process takes place in the mitochondria of cells and involves a series of enzymatic reactions within the citric acid cycle, also known as Krebs Cycle or TCA cycle.

Aerobic vs Anaerobic Respiration

  • Respiration can be either aerobic (using oxygen) or anaerobic (without using oxygen).
  • In aerobic respiration, glucose is completely broken down into carbon dioxide and water, and a large amount of ATP is produced.
  • Anaerobic respiration involves the partial breakdown of glucose in the absence of oxygen, resulting in the production of lesser amounts of ATP and other compounds like lactic acid or ethanol.

Stages of Aerobic Respiration

  • The four stages of aerobic respiration include glycolysis, link reaction, the Krebs cycle, and oxidative phosphorylation.
  • Glycolysis is the first step, where glucose is broken down into pyruvate, releasing enough energy to produce 2 ATP molecules.
  • Link reaction is the second stage, where pyruvate is decarboxylated, releasing a molecule of carbon dioxide and producing an acetyl group which combines with coenzyme A to form acetyl CoA.
  • The Krebs Cycle or citric acid cycle is the third stage where the acetyl CoA is further broken down, releasing two more molecules of CO2 and transferring the energy to NADH.
  • Oxidative phosphorylation is the final stage. Here, the electrons from NADH are transferred through a series of protein complexes in the inner mitochondrial membrane, which drives ATP synthesis.

Role in Metabolic Processes

  • The ATP generated via respiration powers various vital cellular processes, including active transport, protein synthesis, and muscle contraction.
  • The carbon dioxide generated in the process is exhaled as a waste product by the organism.

Respiration and Homeostasis

  • Cellular respiration is not only vital for energy production, but it also plays a crucial role in maintaining homeostasis within a cell.
  • It helps to maintain the pH balance in the body by buffering the acids produced during metabolic activities.
  • The heat produced during respiration also aids in maintaining the body’s temperature.