<prompt> Ammonia is toxic to the brain because it leads to depletion of which substrate?SuccinateAlpha ketoglutarateIsocitrateFumarate  <response>: Ans. B. Alpha ketoglutarateAmmonia reacts with Glutamate to form Glutamine. The Glutamate is formed from alpha keto glutarate an intermediate of TCA Cycle. So alpha ketoglutarate is depleted. 