DNA Length & Genome Sizes — NEET Biology
✅ Asked in NEET 2022DNA is a long polymer of deoxyribonucleotides. The length of DNA is usually defined as number of nucleotides (or a pair of nucleotide referred to as base pairs) present in it. This also is the characteristic of an organism. For example, a bacteriophage known as φX174 has 5386 nucleotides, Bacteriophage lambda has 48502 base pairs (bp), Escherichia coli has 4.6 × 106 bp, and haploid content of human DNA is 3.3 × 109 bp. Let us discuss the structure of such a long polymer.
NTA tests your ability to recall exact genome sizes across organisms—from φX174 (5386 nucleotides) to humans (3.3 × 10⁹ bp). Students often confuse base pairs (bp) with nucleotides; remember that one bp = two nucleotides in double-stranded DNA. The key trap: mixing up the units or forgetting the exponential notation for large organisms. To score correctly, memorize the order of magnitude: bacteria < E. coli < humans, and distinguish between single-stranded viruses (counted as nucleotides) and double-stranded DNA (counted as bp). This concept bridges genomic comparison, evolution, and DNA structure—core NEET topics.
Match List-I with List-II: (NEET 2022 Phase 2) List-I: (a) Bacteriophage φX174 (b) Bacteriophage lambda (c) Escherichia coli (d) Haploid content of human DNA List-II: (i) 48,502 base pairs (ii) 5386 nucleotides (iii) 3.3 × 10⁹ base pairs (iv) 4.6 × 10⁶ base pairs Choose the correct answer from the options given below:
Through deep analysis of NEET and NTA, 88 of 90 questions from the NEET 2026 paper were matched straight from the MedicNEET Biology question bank.
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