Chemical Composition of Living Organisms — NEET Biology
📚 Practice ConceptThere is a wide diversity in living organisms in our biosphere. Now a question that arises in our minds is: Are all living organisms made of the same chemicals, i.e., elements and compounds? You have learnt in chemistry that there are 92 naturally occurring elements. Perform a chemical analysis on a plant tissue, animal tissue or a microbial paste, we obtain a list of elements like carbon, hydrogen, oxygen and several others and their respective content per unit mass of a living tissue. If the same analysis is performed on a piece of earth's crust as an example of non living matter, we observe that all elements are present. However, a closer examination reveals that the relative abundance of carbon and hydrogen with respect to other elements is higher in any living organism than in earth's crust (Table 9.1).
Match the following elemental components with their characteristics in living and non-living matter: Column I (Element) A. Oxygen B. Hydrogen C. Carbon D. Silicon E. Nitrogen Column II (Characteristic) i. Most abundant element in the human body. ii. Constitutes 0.03% of Earth’s crust. iii. Constitutes 0.14% of Earth’s crust. iv. Its relative abundance is higher in Earth’s crust (27.7%) than in the human body (negligible). v. Present as very little in Earth’s crust, but 3.3% in the human body.
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