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Assertion (A) : Agrobacterium… (Class 12 Biology 2024, Q15)

questionbuddy.in/q/cbse-12-biology-2024-57-1-1-q15-agrobacterium-tumefaciens-pathogen-several-monocot

BiologyCBSE Class 12 · Board exam 2024, set 57/1/1 · 1 mark · Assertion-reason

CBSE Class 12 Biology 2024: question 15

Set in the CBSE Class 12 board exam of 2024, paper 57/1/1, section A, question 15, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q15 · 1 mark · Assertion-reasonCompetency-basedBiotechnology: Principles and Processes

Assertion (A) : Agrobacterium tumefaciens is a pathogen of several monocot plants.
Reason (R) : It is able to deliver a piece of DNA known as 'T-DNA' to transform normal plant cells into a tumor.

  1. (A)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
  2. (B)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
  3. (C)Assertion (A) is true, but Reason (R) is false.
  4. (D)Assertion (A) is false, but Reason (R) is true.

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

Check which group of plants this bacterium infects.

Hint 2

NCERT says it is a pathogen of dicots.

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. The assertion is false: Agrobacterium tumefaciens infects dicot plants, not monocots.

    ½ mark

  2. The reason is true: it transfers its T-DNA into plant cells and causes tumours (crown gall).

    ½ mark

Answer: (D)

Where the marks are

  • A is false and R is true (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Biotechnology: Principles and Processes, 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.