GATE 2023 MA – Question 8
Passage: DNA information is used to synthesize proteins necessary for life. DNA consists of nucleotides Adenine (A), Thymine (T), Cytosine (C), and Guanine (G), so its information can be viewed as their sequence. DNA has coding and non-coding regions. Coding regions, read in groups of three to produce amino acids, constitute about 2% of human DNA. The passage gives CCG as coding for glycine and GGA for proline. Amino acids assemble into proteins. Based only on the passage, which inferences follow with certainty? (i) Most human DNA has no role in protein synthesis. (ii) The function of about 98% of human DNA is not understood.
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Correct answer: (D) Neither (i) nor (ii)
Explanation
The passage quantifies direct coding regions. It does not exclude other roles of non-coding regions in synthesis, and says nothing about how well their functions are understood. Neither inference is entailed. **D**. The nucleotide examples are reproduced as passage content; they are unnecessary to this inference.