1995 General Studies, all questions

UPSC Prelims 1995 · General Studies

Question 125: Science and Technology

Which of the following elements are present in all proteins? I. Carbon II. Hydrogen III. Oxygen IV. Nitrogen Select the correct answer from the codes given below:

aI and II
bI, II and IV
cI, III and IV
dI, II, III and IV

AnswerThe answer is (d).

All proteins are chains of amino acids, and every amino acid contains carbon, hydrogen, oxygen and nitrogen. Many proteins also contain sulphur, and some contain phosphorus or metals, but these four are present in all. Carbohydrates and fats lack nitrogen. Remember: C, H, O and N are in all proteins.

  • I. Carbon is in every amino acid.
  • II. Hydrogen is in every amino acid.
  • III. Oxygen is in every amino acid.
  • IV. Nitrogen is in the amino group of every amino acid.
Why each option is right or wrong
  • (a) Incomplete: oxygen and nitrogen are also present in all proteins.
  • (b) Leaves out oxygen.
  • (c) Leaves out hydrogen.
  • (d) Right: all four elements.

Explanation: written by UPSC Grade, not by UPSC.

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Source: UPSC, Civil Services (Preliminary) Examination 1995, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.