Inhibition of glycolysis by increased supply of 02 is called ?
**Core Concept**
The Pasteur effect refers to the inhibition of glycolysis in the presence of oxygen. This phenomenon is a result of the shift in cellular metabolism from anaerobic glycolysis to aerobic respiration when oxygen is available. The Pasteur effect is a critical concept in biochemistry, highlighting the adaptability of cellular metabolism to changing environmental conditions.
**Why the Correct Answer is Right**
The Pasteur effect occurs due to the increased activity of pyruvate dehydrogenase (PDH) and the subsequent conversion of pyruvate to acetyl-CoA, which enters the citric acid cycle. As a result, the accumulation of ATP and NADH in the electron transport chain reduces the need for glycolysis, leading to its inhibition. This shift in metabolism is mediated by the allosteric regulation of key enzymes involved in glycolysis, such as phosphofructokinase-1 and pyruvate kinase.
**Why Each Wrong Option is Incorrect**
**Option A:** The Crabtree effect is the opposite phenomenon, where glycolysis is increased in the presence of oxygen, particularly in certain cancer cells and yeast. This effect is not related to the inhibition of glycolysis by increased oxygen supply.
**Option C:** There is no such phenomenon as the "Lewis effect" related to glycolysis or cellular metabolism. The correct term is the Pasteur effect.
**Option D:** While the Pasteur effect is a well-documented phenomenon, the other options are incorrect, making this option incorrect as well.
**Clinical Pearl / High-Yield Fact**
The Pasteur effect has implications for our understanding of cellular metabolism in various disease states, including cancer, where altered metabolism contributes to tumor growth and resistance to therapy. Understanding the Pasteur effect can provide valuable insights into the development of targeted therapies that exploit these metabolic shifts.
✓ Correct Answer: B. Pasteur effect