1. The receptors for thirst are located in a part of the brain called the hypothalamus. These receptors, called osmoreceptors, are stimulated by an increase in blood osmolality. Imagine a man who has just landed on a desert island. Trace the course of events leading to his sensation of thirst. Can he satisfy his thirst by drinking seawater? Explain.
2. Using letters A, B, C, D, and E for molecules, illustrate how these would interrelate in an unbranced metabolic pathway. Then, illustrate a metabolic pathway in which C branches to form D and E. Describe how your two pathways would be affected by an inborn error of metabolism between C and D.
3. Explain the etiology of phenylketonuria (PKU)