B) WRITE a brief (between 150-200 words) email to a scientific colleague that explains (IN YOUR OWN WORDS) how the cholera bacterium causes diarrhea AT THE CELLULAR LEVEL and what role OSMOSIS plays in this.

The bacterium Vibrio cholerae is the primary cause of cholera disease that mainly infects the small intestine and primarily leads to the dehydration of the body.

Explanation:

The genetic analysis reveals that the aforementioned causative bacteria surpass the acidic conditions of the stomach and eventually reaches the intestinal wall and attaches to it. This is followed by the production of toxic protein by the bacterium. This protein is taken inside the cell via receptor mediated endocytosis followed by its binding to the host protein Arf6. This binding leads to the production of cAMP that results in the dehydration process. This mechanism leads to excessive accumulation of chloride ion in the intestine preventing the entry of sodium ion.

These two ions are associated with the creation of water-salt environment in the intestine that leads to tremendous diarrhea via the process of osmosis.

Hence, we can say that cholera bacterium affects the individuals at the cellular level and osmosis plays a vital role in the process.