Question

extreme toxicity is due to fluoroacetate, a potent metabolic poison that is present in all parts of the plant. in the body, fluoroacetate is converted into fluorocitrate, which irreversibly binds the enzyme that converts citrate to isocitrate in step 2 of the krebs cycle. as a result, the cycle is unable to proceed past step 1. based on the model of the krebs cycle shown above, which of the following best describes an effect of gifblaar poisoning? elevated levels of alpha - ketoglutarate would be found in the blood and urine. isocitrate would accumulate in tissues throughout the body. atp would be depleted, inhibiting many biological processes. the production of nadh and fadh2 would decrease, but atp levels would remain constant.

Explanation:

Step1: Analyze the Krebs cycle disruption

Since fluorocitrate binds the enzyme for citrate - isocitrate conversion (step 2), the cycle stops at step 1.

Step2: Check each option

• Option 1: Alpha - ketoglutarate is formed after isocitrate (step 3). Since cycle stops at step 1, no alpha - ketoglutarate.
• Option 2: Isocitrate is formed in step 2. Cycle stops at step 1, so no isocitrate accumulation.
• Option 3: ATP is produced in step 5 (and also from NADH and FADH₂ in electron transport chain). If cycle stops early (step 1), less NADH and FADH₂ (from steps 3,4,6) are produced. Less NADH and FADH₂ means less ATP from electron transport chain. So ATP is depleted.
• Option 4: NADH (steps 3,4) and FADH₂ (step 6) are produced in later steps. Cycle stops at step 1, so their production decreases. And since ATP is also made from NADH and FADH₂ in electron transport chain, ATP levels do not remain constant.

Answer:

ATP would be depleted, inhibiting many biological processes.