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(a) Write the characteristics… (Class 12 Biology 2023, Q24)

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BiologyCBSE Class 12 · Board exam 2023, set 57/1/1 · 3 marks · Short answer

CBSE Class 12 Biology 2023: question 24

Set in the CBSE Class 12 board exam of 2023, paper 57/1/1, section C, question 24, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q24 · 3 marks · Short answerBiotechnology and its Applications

(a) Write the characteristics of 'stem cells'.
(b) From where can one obtain 'stem cells' in humans ?
(c) State any two applications of 'stem cells' in curing human diseases.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 57/1/1.

Hints

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

Hint 1

Stem cells have two defining properties: one about dividing and one about becoming other cells.

Hint 2

Think of embryonic and adult sources, such as the blastocyst or bone marrow.

Hint 3

Which diseases involve loss of specific cells that could be replaced?

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) Stem cells have the ability of self-renewal: they can divide repeatedly to produce more stem cells.

    ½ mark

  2. They can also differentiate into any kind of specialised cell, tissue or organ.

    ½ mark

  3. (b) Stem cells can be obtained from the inner cell mass of the blastocyst (embryonic stem cells), umbilical cord blood or bone marrow (any one).

    1 mark

  4. (c) Application 1: treating diabetes by forming insulin-producing islets of Langerhans cells.

    ½ mark

  5. Application 2: repairing spinal cord injuries or heart tissue damage, or restoring vision by injecting stem cells (any other correct application, such as rheumatoid arthritis or cystic fibrosis).

    ½ mark

Answer: (a) Self-renewal and ability to differentiate into any cell type; (b) inner cell mass of blastocyst/umbilical cord/bone marrow; (c) e.g. diabetes (islet cells), spinal cord injury/heart disease/vision restoration

Where the marks are

  • Self-renewal (½ mark)
  • Differentiation into any cell/tissue (½ mark)
  • One correct source of stem cells (1 mark)
  • Two correct medical applications (½ + ½ mark)

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 paper2023 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.