Question 66: Which one of the following statements is correct?
(1) The bone in human body is an inert and unchanging substance.
(2) Mg plays roles in neuromuscular function and interneuronal transmission.
(3) The daily requirement of Mg and Ca in the human body is estimated to be 0.2\!-\!0.3 \ \mathrm{g}.
(4) All enzymes that utilise ATP in phosphate transfer require Ca as the cofactor.
Answer: Option (3)
Explanation:
Bones in the human body are not inert; they undergo continuous remodeling,
so statement (1) is incorrect.
Magnesium mainly acts as a cofactor for enzymes and stabilizes ATP,
while calcium plays a major role in neuromuscular function and interneuronal transmission,
making statement (2) incorrect.
The daily dietary requirement of magnesium and calcium in the human body is approximately
0.2\!-\!0.3 \ \mathrm{g}, which makes statement (3) correct.
Enzymes that utilize ATP in phosphate transfer generally require magnesium ions,
not calcium, as a cofactor, so statement (4) is incorrect.
Hence, the correct statement is option (3).