Which reactions replace citric acid cycle intermediates that are used for biosynthesis?

Anapleurotic reactions play a crucial role in replenishing citric acid cycle intermediates that may be diverted for various biosynthetic pathways. These reactions help maintain the balance of the cycle, ensuring that there are enough intermediates available for continuous cellular respiration and energy production. For instance, the conversion of pyruvate into oxaloacetate via pyruvate carboxylase is a classic example of an anapleurotic reaction, as it provides oxaloacetate needed to combine with acetyl-CoA, keeping the cycle running smoothly. This is particularly important because the intermediates can be used for synthesizing important biomolecules such as amino acids, nucleotide bases, and other cellular components, thereby connecting metabolism and biosynthesis.