Question

All of the following tricarboxylic acid cycle intermediates may be added or removed by other metabolic pathways except A. cirrate. B. fumarate. C. isocitrate. D. \(\alpha\) -ketoglutarate. E. oxaloacetate.

Short answer

A. Cirrate (Citrate) B. Fumarate C. Isocitrate D. α-ketoglutarate E. Oxaloacetate Answer: The question, as written, is incorrect because all the TCA cycle intermediates mentioned in the options can be added or removed by other metabolic pathways.

Step-by-step solution

List the intermediates of the TCA cycle

The intermediates of the tricarboxylic acid cycle are: 1. Citrate 2. Isocitrate 3. \(\alpha\) -ketoglutarate 4. Succinyl-CoA 5. Succinate 6. Fumarate 7. Malate 8. Oxaloacetate Step 2: Understanding the roles of the intermediates in other metabolic pathways

Explore the roles of intermediates in other metabolic pathways

The intermediates of the TCA cycle are involved in various other metabolic pathways, such as: 1. Citrate: Fatty acid synthesis and regulation of glycolysis 2. Isocitrate: Synthesis of \(\alpha\) -ketoglutarate and isocitrate dehydrogenase regulation 3. \(\alpha\) -ketoglutarate: Amino acid metabolism and nucleotide synthesis 4. Succinyl-CoA: Heme synthesis and ketone body utilization 5. Succinate: Regeneration of fumarate in the urea cycle 6. Fumarate: Amino acid metabolism and purine synthesis 7. Malate: Gluconeogenesis and fatty acid synthesis 8. Oxaloacetate: Gluconeogenesis and amino acid metabolism Step 3: Analyzing the options provided in the question

Analyze the given options in the question

The options provided in the question are: A. Cirrate (Note that Cirrate is not a legitimate intermediate name but is probably the misspelled name for Citrate) B. Fumarate C. Isocitrate D. \(\alpha\) -ketoglutarate E. Oxaloacetate Step 4: Identifying the correct option

Select the correct option

Based on the understanding of intermediates and their roles in other metabolic pathways, we find that all the TCA cycle intermediates mentioned in the options can be added or removed by other metabolic pathways. Thus, the question as written is incorrect as there is no intermediate in the list that can't be added or removed by other metabolic pathways.