Question

The site of action and substrate of rennin are respectively

• A. mouth and starch
• B. small intestine and protein
• C. stomach and casein
• D. stomach and fat

Answer 1

Answer: (C)

stomach and casein

Answer 2

In stomach, rennin acts on casein (milk protein) and converts it into paracasein. In the presence of calcium ions, paracasein is converted into calcium paracaseinate, ultimately leading to milk coagulation Casein ${ ->[Rennin] }$ Paracasein ${ ->[ca^{+2}] }\underset{\text{ (Milk coagulation).}}{\text{Calcium paracaseinate}}$