Problem
I. The cell membrane is especially adept at filtering out what can and cannot come into a cell. Using the basic chemistry of the phospholipid bilayer, explain in detail how it excels at this job. Then, for each of the compounds listed below, identify if they can be transported passively or actively across the membrane, and why.
i. Lactose
ii. Potassium Chloride
iii. Cholesterol
II. Metabolism and fluid balance in the body are linked in important ways. Identify one metabolic process and explain how it relates to the balance of a key blood solute. Be detailed in your response.