Question

Which of the following are the most abundant elements in the living cells?
A. C, H, S and P
B. C, O, N and P
C. C, H, O and N
D. C, H, Mg and Ca

Answer 1

Hint:- Living organisms comprise only a small number of certain components, which make up 96.5% of the weight of an organism. The building blocks of the compounds that make up our organs and muscles, the bulk of our diet needed for humans, are these components.

Complete step-by-step solution:-
Option A is incorrect. Phosphorus and sulphur are both common elements that are important for the structure of nucleic acids and amino acids. Whereas other elements are important to any living thing and make up 99% of the mass of protoplasm collectively.
Option B is incorrect. To structure nucleic acids, phosphorus is essential. For all living organisms, nitrogen is important because it is a big part of amino acids, which are the building blocks for proteins and nucleic acids such as DNA. Whereas other elements are important to any living thing and make up 99% of the mass of protoplasm collectively.
Option C is correct. In living things, carbon, hydrogen, oxygen, and nitrogen are the most common elements. A biological molecule composed of atoms of carbon (C), hydrogen (H) and oxygen (O) is a carbohydrate. Proteins are made up of amino acids containing amine (-NH2) that are organic compounds (C, H, and O) together with a side chain (R group) unique to each amino acid. Each nucleotide consists of an aromatic base containing nitrogen attached to a pentose sugar (C, H, and O), which in turn is attached to a group of phosphates. Thus, C, H, O and N consist of major macromolecules and are therefore the most abundant elements in living cells.
Option D is incorrect. Calcium plays a major role in the processes of signal transduction, where it serves as a second messenger, in the release of neurotransmitters from neurons, in the contraction of all forms of muscle cells, and in fertilisation. A crucial mineral nutrient for life, magnesium is present in every form of cell in every organism. For instance, in order to be biologically active, ATP (adenosine triphosphate), the key energy source in cells, must bind to a magnesium ion.
So, the correct answer is Option C.

Note:- Thousands of large molecules combine and form the atoms of the basic elements. These large molecules make up cell structures and conduct many life-critical processes, such as organisation, metabolism, responsiveness, movement, and reproduction.