Important functions of calcium are :
(i) Formation of bone
(ii) Regulates the heart beat
(iii)Blood coagulation
(iv)Cell Membrane permeability Codes:

Question

Important functions of calcium are : 
(i) Formation of bone 
(ii) Regulates the heart beat 
(iii)Blood coagulation 
(iv)Cell Membrane permeability Codes:

Accepted Answer

The correct option is 4: (i), (ii), (iii) and (iv)

Calcium is an essential macro-mineral that serves far beyond its primary role as a structural component of the skeleton. It is one of the most vital ions in human physiology, acting as a universal second messenger that governs many cellular and systemic functions. Therefore, all the listed options represent crucial, non-negotiable functions of calcium in the body. Firstly, the Formation of bone (i) is its most widely recognized role; approximately 99% of the body's calcium is stored in the bones and teeth, where it combines with phosphate to form hydroxyapatite crystals, providing the rigidity and structural framework for the body. Secondly, calcium Regulates the heart beat (ii) and all muscle contractions. In cardiac muscle cells, the influx and release of calcium ions are the precise triggers that initiate the contraction and relaxation cycles, fundamentally controlling the rhythm and force of the heart's pumping action. A deficiency or excess of calcium can severely disrupt cardiac function. Thirdly, calcium is absolutely essential for Blood coagulation (iii). It is known as Factor IV in the complex clotting cascade. Without the presence of calcium ions, the various clotting factors cannot interact properly to form the fibrin clot that stops bleeding, rendering the clotting process non-functional. Finally, calcium critically influences Cell Membrane permeability (iv). Calcium ions control the opening and closing of ion channels in cell membranes, regulating the movement of other ions and molecules into and out of the cell. This control is vital for nerve impulse transmission, hormone secretion, and maintaining the structural integrity and signaling capability of the cell membrane itself. Given the indispensable nature of all these processes, Option 4, which includes all four functions, is the comprehensive correct answer.

The incorrect option is 1: (i) and (iv)
Option 1 suggests that only (i) Formation of bone and (iv) Cell Membrane permeability are important functions of calcium. While these roles are certainly important, this option is fundamentally flawed because it ignores two other primary, life-sustaining roles of calcium. The body's ability to stop bleeding through blood coagulation (iii) is critically dependent on calcium, and the rhythmic pumping of the heart (ii) is directly regulated by calcium flow into cardiac muscle cells. These functions are immediate and vital for survival. Since a major mineral's functions are holistic and interconnected, selecting only two out of the four vital roles fails to capture the full physiological importance of the ion. Therefore, this answer choice provides an incomplete and misleading view of calcium's total functionality.

The incorrect option is 2: (ii), (iii) and (iv)
Option 2 proposes that the important functions are (ii) Regulates the heart beat, (iii) Blood coagulation, and (iv) Cell Membrane permeability. This choice is incorrect because it consciously excludes the most abundant and universally understood function of calcium, which is the Formation of bone (i). Calcium is the foundational mineral of the skeletal structure, where it provides mechanical strength and serves as a reservoir for all other calcium-dependent processes. This structural role is so dominant that the body uses bone calcium as a buffer to maintain the precise plasma concentration needed for all the other functions. To discuss the important functions of calcium without acknowledging its structural role in bone and teeth is a major and unacceptable omission in nutritional science.

The incorrect option is 3: (iii) and (iv)
Option 3 limits the important functions to only (iii) Blood coagulation and (iv) Cell Membrane permeability. This option is the most incorrect because it overlooks the two most substantial physiological roles: bone formation (i) and heart beat regulation (ii). Bone formation accounts for the vast majority of calcium's presence in the body and is a key public health concern. Heart regulation is an immediate, life-critical function; its failure is incompatible with life. Focusing only on blood clotting and cell permeability, while valid functions, minimizes the biological scope of this essential macro-mineral by ignoring the two functions that form the largest physiological impact of calcium.