Final answer:
The amphibolic pathway is a type of metabolic pathway that encompasses both anabolic (building molecules) and catabolic (breaking down molecules) processes. The citric acid cycle is an example of such a pathway, demonstrating its vital role in the metabolism across various organisms.
Step-by-step explanation:
The term “amphibolic pathway” refers to a metabolic pathway that has both anabolic and catabolic functions. Anabolic pathways are those building larger molecules from smaller ones, which requires energy. On the other hand, catabolic pathways involve the breaking down of larger molecules into smaller molecules, which releases energy. This dual function is essential for the cell's energy balance.
The citric acid cycle, also known as the tricarboxylic acid (TCA) cycle, is a prime example of an amphibolic pathway. It plays a crucial role in both the oxidation of carbohydrates, fats, and proteins (catabolic role) and the synthesis of carbohydrates, amino acids, and fats (anabolic role). The flexibility of this pathway allows it to be a central hub in the metabolic networks, facilitating the interconversion of biomolecules for various physiological needs.
Therefore, the correct answer to the student's question is d) A pathway that is both anabolic and catabolic in nature. This clarification highlights the integrative role of such pathways within the metabolism of almost all organisms, reflecting the interconnected nature of biological processes.