Final answer:
The anaplerotic role of pyruvate carboxylase in cellular metabolism is the replenishment of oxaloacetate in the citric acid cycle, essential for the cycle's continuity and efficiency.
Step-by-step explanation:
The anaplerotic contribution of pyruvate carboxylase in cellular metabolism is significant because it is involved in the replenishment of oxaloacetate in the citric acid cycle (also known as the Kreb's cycle). This replenishment is crucial for the continuation of the citric acid cycle, especially when intermediates of the cycle are withdrawn for the biosynthesis of other compounds, such as amino acids, which can lead to a decrease in the concentration of oxaloacetate within the cycle.
Anaplerosis helps maintain the proper function of the citric acid cycle by replenishing these intermediates. In the specific case of pyruvate carboxylase, it catalyzes the reaction where pyruvate is carboxylated to form oxaloacetate. This newly formed oxaloacetate then enters the citric acid cycle, maintaining the cycle's efficiency and enabling its vital role in energy production, as it is critical for the synthesis of ATP and other molecules like NADH and FADH2.