What is the primary outcome of glycolysis in cellular respiration?

• A. Synthesis of fatty acids
• B. Formation of carbon dioxide
• C. Production of oxygen
• D. Conversion of glucose into pyruvate

Answer: (D)

Verified step by step guidance

1. Begin by understanding the process of glycolysis, which is the first step in cellular respiration. Glycolysis occurs in the cytoplasm of the cell and involves the breakdown of glucose, a six-carbon sugar, into two molecules of pyruvate, a three-carbon compound.
2. Recognize that glycolysis is an anaerobic process, meaning it does not require oxygen. This is important because it allows cells to generate energy even in the absence of oxygen.
3. During glycolysis, glucose undergoes a series of enzymatic reactions. These reactions involve the investment of ATP to phosphorylate glucose and its intermediates, which helps in destabilizing the glucose molecule and facilitates its breakdown.
4. As glycolysis progresses, ATP and NADH are produced. Specifically, two molecules of ATP are consumed, and four molecules of ATP are produced, resulting in a net gain of two ATP molecules. Additionally, two molecules of NADH are generated, which are used in later stages of cellular respiration.
5. Finally, the primary outcome of glycolysis is the conversion of glucose into two molecules of pyruvate. This pyruvate can then enter the mitochondria to be further processed in the Krebs cycle and oxidative phosphorylation, if oxygen is present, to produce more ATP.