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Answer the following. (Science 2025 31/5/1 Q29)

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ScienceCBSE Class 10 · Board exam 2025, set 31/5/1 · 3 marks · Short answer

CBSE Class 10 Science 2025: question 29

Set in the CBSE Class 10 board exam of 2025, paper 31/5/1, section C, question 29, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q29 · 3 marks · Short answerLife Processes

Answer the following.

  1. (a)

    Write the name and one function of respiratory pigment found in human beings.

    0 marks
  2. (b)

    Why do lungs always contain a residual volume of air?

    0 marks
  3. (c)

    Why is ATP known as energy currency of the living beings?

    0 marks

Source: official question paper from cbse.gov.in (PDF). See it in the full 2025 board paper, set 31/5/1.

Hints

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

Hint 1

The pigment is found in RBCs and gives blood its red colour.

Hint 2

Gas exchange in the alveoli must continue even while you breathe out.

Hint 3

Think of ATP as money that is earned in respiration and spent by the cell's activities.

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) The respiratory pigment in humans is haemoglobin, present in red blood cells.

    ½ mark

  2. (a) Function: it has a high affinity for oxygen. It takes up oxygen in the lungs and carries it to the tissues that are deficient in oxygen.

    ½ mark

  3. (b) The lungs always keep a residual volume of air so that there is enough time for oxygen to be absorbed into the blood and for carbon dioxide to be released, even during exhalation.

    1 mark

  4. (c) Energy released during cellular respiration is stored in ATP. Breaking its terminal phosphate bond releases energy that the cell uses for various processes such as muscle contraction, protein synthesis and conduction of nerve impulses. ATP works like currency in this way, so it is called the energy currency of the cell.

    1 mark

Answer: (a) Haemoglobin – carries O₂ from lungs to tissues; (b) to allow sufficient time for O₂ absorption and CO₂ release; (c) ATP stores energy and supplies it for all cellular activities.

Where the marks are

  • Names haemoglobin (½ mark)
  • Function: carries oxygen from lungs to tissues (½ mark)
  • Residual air gives time for O₂ absorption and CO₂ release (1 mark)
  • ATP stores and supplies energy for cellular processes (1 mark)

Revise the chapter

  • Chapter: Life Processes (notes, formulas, where marks are lost and every past question)
Practise this chapterBoard-style questions from Life Processes, one at a time, marked against the answer key and marking points.Back to the full paper2025 board paper, set 31/5/1: 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.