AFAA Personal Trainer Certification Practice Exam

Which of the following best describes glycolysis?

1. A process that requires oxygen to produce ATP

2. A sequence that processes amino acids

3. A metabolic pathway breaking down sugars for energy

4. A cycle for regenerating NAD+

The correct answer is: A metabolic pathway breaking down sugars for energy

Glycolysis is best described as a metabolic pathway that breaks down sugars for energy. This process occurs in the cytoplasm of cells and involves the enzymatic conversion of glucose, which is a six-carbon sugar, into two molecules of pyruvate, a three-carbon compound. During glycolysis, energy is invested initially to convert glucose into a more reactive form, after which energy is harvested in the form of ATP and NADH. The overall purpose of glycolysis is to extract energy from carbohydrates, highlighting its role in cellular respiration as a fundamental step for energy production. In contrast, the other options do not accurately capture the essence of glycolysis. The process itself does not require oxygen, although it can operate in both anaerobic and aerobic conditions. Glycolysis specifically pertains to carbohydrate metabolism, rather than amino acid processing, thereby making the option concerning amino acids irrelevant. Additionally, while glycolysis does contribute to the regeneration of NAD+ through the conversion of NADH during subsequent reactions, its primary function is not a cycle for regenerating NAD+, but rather the breakdown of sugars. Therefore, C most accurately encapsulates the essence of glycolysis.