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Sometimes while running, the… (Class 10 Science 2024, Q23a)

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ScienceCBSE Class 10 · Board exam 2024, set 31/5/1 · 2 marks · Very short answer

CBSE Class 10 Science 2024: question 23(a)

Set in the CBSE Class 10 board exam of 2024, paper 31/5/1, section B, question 23(a), for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q23(a) · 2 marks · Very short answerCompetency-basedLife Processes

Sometimes while running, the athletes suffer from muscle cramps. Why? How is the respiration in this case different from aerobic respiration?

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 31/5/1.

Hints

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

Hint 1

During hard exercise, can the blood supply enough oxygen to the muscles?

Hint 2

When oxygen is short, pyruvate is converted into a different 3-carbon compound in muscle cells. Compare its products with those of aerobic respiration.

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. During vigorous running, oxygen supply to the muscle cells falls short. Pyruvate is then broken down anaerobically into lactic acid, and the build-up of lactic acid in the muscles causes cramps.

    1 mark

  2. Difference: aerobic respiration occurs in the presence of oxygen and gives + water + more energy. Here respiration occurs in the absence (lack) of oxygen and gives lactic acid + less energy.
    Glucose Pyruvate Lactic acid + Energy

    1 mark

Answer: Cramps are due to lactic acid build-up from anaerobic respiration. This respiration occurs without enough oxygen and gives lactic acid and less energy; aerobic respiration uses oxygen and gives , water and more energy.

Where the marks are

  • States that lactic acid accumulates in muscles and causes cramps (1 mark)
  • Contrasts it with aerobic respiration (presence/absence of oxygen or products versus lactic acid) (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 paper2024 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.