Question

About 98 percentage of the mass of every living organism is composed of just six elements including carbon, hydrogen, nitrogen, oxygen and
a. Sulphur and magnesium
b. Magnesium and sodium
c. Phosphorus and sulphur
d. Calcium and phosphorus

Answer 1

Hint: Every cell is made up of a variety of biomolecules and molecular aggregates. These biomolecules are important for the normal functioning and metabolism of the body. The study of the molecules of the living organism and chemical changes occurring in them is called biochemistry.

Complete answer:
The various bio elements present in the body are categorized into three groups:
> Principal or major elements- It includes oxygen, carbon, hydrogen and nitrogen. These constitute about 95% of the cell’s weight. They include non-metals and their biological importance is that they form very stable covalent bonds.
- Oxygen is required for respiration and is the abundant and important element in living organisms. It helps in the oxidation of food and formation of energy.
- Carbon and hydrogen are other important elements that are an important constituent of carbohydrates, fats, etc.
- Nitrogen is an important constituent of amino acids that polymerize to form proteins. Besides these the other two important elements are calcium and phosphorus.
- Phosphorus is an important constituent of DNA in the cells and is also required for the formation of ATP (adenosine triphosphate) which is the energy currency of the cells.
- Calcium is the most abundant mineral as it is an important component of the bones.

> Minor or trace elements- It includes iron, potassium, chlorine, etc. which collectively form only 2% of the protoplasm weight.

> Ultra-trace elements- These elements form 0.001% of the protoplasm, for example, Copper ions, zinc ions, boron, etc.

Hence, the correct answer is option (D).

Note: The chemical analysis of the earth crust revealed that the elements present in it are the same as the elements found in the tissues of living organisms. But the relative abundance of these elements in earth’s crust is different from that present in the body.