Explanation
- A
Chlorophyll
Option (a) claims that nitrogen is an essential constituent of chlorophyll. This is incorrect because chlorophyll molecules contain a central magnesium atom surrounded by a porphyrin ring made of carbon, hydrogen, oxygen, and nitrogen.
- B
RNA
Option (b) claims that nitrogen is an essential constituent of RNA. This is incorrect because ribonucleic acid contains nitrogenous bases along with ribose sugar and phosphate groups.
- C
DNA
Option (c) claims that nitrogen is an essential constituent of DNA. This is incorrect because deoxyribonucleic acid is built from nucleotides that include nitrogenous purine and pyrimidine bases.
- D
Carbohydrate
Option (d) claims that nitrogen is not an essential constituent of carbohydrate. Official key is (d) because carbohydrates are organic compounds composed strictly of carbon, hydrogen, and oxygen, containing no nitrogen.
Summary. Official key is (d) as carbohydrates consist exclusively of carbon, hydrogen, and oxygen atoms. Chlorophyll contains a porphyrin ring structure where nitrogen is a vital coordinating element. Both RNA and DNA rely heavily on nitrogenous bases to store genetic information. Thus, carbohydrates stand apart from proteins, nucleic acids, and photosynthetic pigments by lacking nitrogen entirely.
Same topic · past papers
UPPSC has asked this before
These previous-year questions sit on the same topic. Open one to practise the earlier ask.
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2021 · Q47 · UPPGS
At the time of second wave of COVID-19 Pandemic, which institute had demonstrated the conversion of nitrogen generator into oxygen generator? -
2024 · Q108 · UPPGS
Given below are two statements, one is labelled as Assertion (A) : and the other as Reason (R). Assertion (A): CO₂, SO₂, and NO₂ gases get dissolved in rain water and produce acid rain. Reason (R): Atmospheric air is polluted due to high concentration of gases like carbon dioxide, sulphur dioxide and oxides of nitrogen. Select the correct answer from the codes given below: -
2019 · Q135 · UPPGS
Which of the following is associated with biological nitrogen fixation?