MCQ Detailed View

The main component of bones and teeth is calcium phosphate, a mineral compound that provides strength, hardness, and structure to the skeletal system. In human bones, calcium phosphate is primarily found in the form of hydroxyapatite crystals (Ca₁₀(PO₄)₆(OH)₂), which are deposited in the protein matrix of collagen fibers, making bones both strong and slightly flexible.Bones are living tissues that constantly undergo remodeling. The combination of collagen (a structural protein) and calcium phosphate minerals allows bones to withstand pressure and weight while avoiding brittleness. In teeth, calcium phosphate forms enamel and dentin, which protect teeth from decay and damage.

Functions of calcium phosphate:

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  Provides rigidity and durability to bones and teeth.

  
  


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  Acts as a reservoir for calcium and phosphorus, essential minerals for many body functions.

  
  


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  Plays a role in nerve transmission, blood clotting, and muscle contraction through calcium release.

  
  

Explanation of other options:

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  Calcium carbonate: Present in shells of marine animals and some parts of bones but not the main component in humans.

  
  


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  Calcium sulphate: Used in plaster of Paris but is not found in significant amounts in the human skeleton.

  
  


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  Calcium nitrate: A chemical compound used in fertilizers, not in human bones.

  
  

Bones store 99% of the body’s calcium, mostly in the form of calcium phosphate. If dietary calcium intake is low, the body draws calcium from bones, leading to bone weakening diseases like osteoporosis. Sources of calcium and phosphorus include milk, dairy products, fish, green leafy vegetables, and nuts.

In conclusion, calcium phosphate is the main component of bones and teeth, making option B (Calcium phosphate) the correct answer for this biology MCQ.