Question

Which of the following is NOT bacterial activity in the human alimentary canal?

• A. Fermentation of carbohydrates and production of methane gas.
• B. Digestion of protein and production of substances like indole, skatole etc.
• C. Synthesis of Vitamin B
• D. Synthesis of Vitamin D

Hint:

Gut bacteria ferment carbohydrates, putrefy proteins and make some vitamins, but one vitamin is made elsewhere.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept
Bacteria in the large intestine act on food that was not digested earlier.

Step 2: Activities they do perform
They ferment carbohydrates and release gases such as methane.
They break down proteins and form indole and skatole.
They synthesise vitamin K and several B vitamins.

Step 3: Vitamin D
Vitamin D is formed in the skin when ultraviolet rays act on a cholesterol derivative. Intestinal bacteria do not make it.

Step 4: Conclusion
So synthesis of vitamin D is the activity not carried out by bacteria.

Final Answer:
Synthesis of vitamin D is not a bacterial activity in the alimentary canal. \[ \boxed{\text{(D) }\text{Synthesis of Vitamin D}} \]