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A stretch of an… (Class 12 Biology SQP 2026-27, Q10)

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BiologyCBSE Class 12 · Sample paper, session 2026-27 · 1 mark · MCQ

CBSE Class 12 Biology sample paper 2026-27: question 10

From the official CBSE sample question paper for 2026-27, section A, question 10, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q10 · 1 mark · MCQMolecular Basis of Inheritance

A stretch of an euchromatin has 200 nucleosomes, how many base pairs (bp) will be there in the stretch and what would be the length of the typical euchromatin?

  1. (A)20,000 bp and 13,000x10 m
  2. (B)10,000 bp and 10,000x10 m
  3. (C)40,000 bp and 13,600x10 m
  4. (D)40,000 bp and 13,900x10 m

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2026-27.

Hints

Open one hint at a time and try again before the next.

Hint 1

Recall the number of bp in one nucleosome.

Hint 2

The distance between adjacent base pairs is 0.34 nm.

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

  1. A typical nucleosome has about 200 bp, so 200 nucleosomes contain bp.

  2. Length m m. Option (C).

    1 mark

Answer: (C) 40,000 bp and 13,600×10⁻⁹ m

Where the marks are

  • Calculates the base pairs and the length correctly (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Molecular Basis of Inheritance, one at a time, marked against the answer key and marking points.Back to the full paperSample paper 2026-27: every question, by section.

The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.