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Answer the following. (Class 12 Biology 2024, Q23)

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BiologyCBSE Class 12 · Board exam 2024, set 57/1/1 · 3 marks · Short answer

CBSE Class 12 Biology 2024: question 23

Set in the CBSE Class 12 board exam of 2024, paper 57/1/1, section C, question 23, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q23 · 3 marks · Short answerBiotechnology and its Applications

Answer the following.

  1. (a)

    Name and write two characteristics of the type of DNA that forms the basis of DNA fingerprinting technique.

    2 marks
  2. (b)

    Mention any two applications of this technique.

    1 mark

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 57/1/1.

Hints

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

Hint 1

This DNA separates as small peaks during density gradient centrifugation.

Hint 2

Why would DNA that differs greatly between people be useful in a court of law?

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) DNA fingerprinting is based on repetitive DNA / satellite DNA, particularly VNTRs (Variable Number of Tandem Repeats).

    1 mark

  2. (a) Characteristics (any two):

    • It does not code for any protein.
    • It forms a large portion of the human genome.
    • It shows a high degree of polymorphism, which makes it unique to each individual.
    1 mark

  3. (b) Applications (any two):

    • Forensic investigations, i.e. identifying criminals.
    • Paternity (parentage) testing.
    • Determining population and genetic diversity, and studying evolution.
    1 mark

Answer: (a) Satellite (repetitive) DNA/VNTR – non-coding, large part of genome, highly polymorphic; (b) forensics, paternity testing (also population/genetic diversity studies)

Where the marks are

  • Names satellite/repetitive DNA/VNTR (1 mark)
  • Any two characteristics (½ + ½ marks)
  • Any two applications (½ + ½ marks)

Revise the chapter

Practise this chapterBoard-style questions from Biotechnology and its Applications, one at a time, marked against the answer key and marking points.Back to the full paper2024 board paper, set 57/1/1: 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.