Final answer:
In the citrate synthase mechanism, oxaloacetate first binds to citrate synthase, and then acetyl CoA adds its acetyl group to form citrate. Citrate synthase releases citrate and regenerates CoA, completing the cycle's first step. C. coa. after; before after;
Step-by-step explanation:
The order of events in the citrate synthase mechanism, which is the initial step of the Citric Acid Cycle (also known as the TCA cycle or Krebs cycle), can be described as follows: First, oxaloacetate binds to the active site of citrate synthase. Next, acetyl CoA enters, and the acetyl group is transferred onto the oxaloacetate, yielding citrate. Finally, citrate is released and CoA is freed to bind to another acetyl group.
This entire process is critical for cellular respiration and occurs in the mitochondria of cells, where oxaloacetate is regenerated at the end of the Citric Acid Cycle to start the process over again with a new molecule of acetyl-CoA. It is an integral part of the metabolic pathway that converts carbohydrates, fats, and proteins into carbon dioxide and water while generating usable energy in the form of ATP.