PYQ-NEET Practice Exam

The principal organic constituent of a living cell in order of relative abundance is proteins. Proteins serve as fundamental components in various cellular functions, acting as enzymes, structural elements, signaling molecules, and transporters. They are composed of long chains of amino acids and can be highly diverse in structure and function, which allows them to play critical roles in metabolism and cell regulation.

In terms of abundance, proteins are present in greater quantities compared to other organic molecules like nucleic acids, carbohydrates, and lipids. Though nucleic acids (such as DNA and RNA) are vital for genetic information and synthesis, they are not as abundant as proteins in most cells. Carbohydrates primarily serve as energy sources and structural components but are typically less abundant than proteins. Lipids, while essential for membrane structure and energy storage, also do not surpass proteins in overall quantity.

Thus, proteins dominate in terms of both structural and functional roles within the cell, making them the most abundant organic constituents in living cells.

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