Final answer:
The symptoms of Cholera are caused by exotoxins produced by the bacterium Vibrio cholerae, which lead to excessive fluid and electrolyte secretion resulting in severe diarrhea.
Step-by-step explanation:
The symptoms of Cholera are due to the action of exotoxins. Specifically, the cholera toxin, an enterotoxin produced by the gram-negative bacterium Vibrio cholerae, is responsible for the severe diarrheal symptoms associated with the disease. This toxin is composed of one A subunit and five B subunits.
The B subunits bind to receptors on the intestinal epithelial cells, allowing the A subunit to enter the cell and activate an intracellular G protein. The activated G protein stimulates adenyl cyclase to increase the cyclic AMP (cAMP) levels, disrupting intestinal cell physiology and causing the cells to secrete excessive fluids and electrolytes into the intestinal tract. This leads to the characteristic "rice-water stool" diarrhea of cholera.
Cholera toxin, produced by the bacterium Vibrio cholerae, is an enterotoxin that causes severe diarrhea by disrupting the normal physiology of intestinal epithelial cells. The toxin activates an intracellular G protein, which leads to the activation of adenyl cyclase and an increase in cyclic AMP concentration. This disrupts the absorption of fluid and electrolytes in the intestines, leading to the characteristic watery diarrhea seen in cholera.
Therefore answer is A)Exotoxins.