When the body is deficient in oxaloacetate, several metabolic pathways are affected. Firstly, acetyl CoA from the fatty acid oxidation pathway cannot effectively enter the citric acid cycle, which is crucial for energy production. This is because oxaloacetate is a necessary substrate for the citric acid cycle to function properly.
Additionally, if oxaloacetate levels are low, some of it may be diverted to gluconeogenesis, the process through which glucose is synthesized from non-carbohydrate sources. This diversion further reduces the amount of oxaloacetate available for the citric acid cycle.
Moreover, the lack of oxaloacetate can also lead to elevated levels of acetyl CoA, which can then be converted into ketone bodies when not utilized in the citric acid cycle. Ketogenesis is a significant alternative pathway that occurs, particularly during periods of fasting or low carbohydrate intake.
Thus, all the given statements (a, b, and c) are true. In summary, a deficiency in oxaloacetate directs the metabolic flow towards gluconeogenesis and the production of ketone bodies, hindering the normal function of the citric acid cycle.