NEET Exam Model Paper 1

Statement a is correct: $Ca^{2+}$ is required to trigger contraction, and $Mg^{2+}$ is required as a cofactor for the myosin ATPase reaction.Statement b is correct: $F$-actin is a polymer made of monomeric $G$-actin molecules.Statement c is wrong: $Ca^{2+}$ binds to troponin C, but it does not displace the troponin complex; it moves tropomyosin away and exposes the myosin-binding sites on actin.Statement d is correct: the globular head of myosin acts as an active ATPase enzyme.Thus, only one statement is wrong.Correct option: 'one'.