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Complete the pathways given… (Class 10 Science 2026, Q13)

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ScienceCBSE Class 10 · Board exam 2026, set 31/2/1 · 3 marks · Short answer

CBSE Class 10 Science 2026: question 13

Set in the CBSE Class 10 board exam of 2026, paper 31/2/1, section A, question 13, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q13 · 3 marks · Short answerLife Processes

Complete the pathways given below, showing the breakdown of glucose.

Identify ‘A’, ‘B’, ‘C’, ‘D’, ‘E’ and ‘F’.

Figure in the paper: Flow chart: Glucose --‘A’--> Pyruvate + Energy. From Pyruvate three branches: in yeast --> ‘B’ + ‘C’ + Energy; in muscle cells --> ‘D’ + Energy; in mitochondria --> ‘E’ + ‘F’ + Energy. See it in the official paper.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2026 board paper, set 31/2/1.

Hints

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

Hint 1

Where in the cell does the first step of glucose breakdown happen?

Hint 2

Compare anaerobic respiration in yeast, lack of oxygen in muscles, and aerobic respiration in mitochondria.

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: Cytoplasm. Glucose (6-carbon) is broken down to pyruvate (3-carbon) in the cytoplasm.

    ½ mark

  2. B: Ethanol (yeast, anaerobic respiration)

    ½ mark

  3. C: Carbon dioxide. B and C may be written in either order.

    ½ mark

  4. D: Lactic acid. This forms in muscle cells when oxygen is in short supply.

    ½ mark

  5. E: Carbon dioxide (aerobic respiration in mitochondria)

    ½ mark

  6. F: Water. E and F may be written in either order.

    ½ mark

Answer: A – Cytoplasm; B – Ethanol; C – Carbon dioxide; D – Lactic acid; E – Carbon dioxide; F – Water (B/C and E/F interchangeable)

Where the marks are

  • A = cytoplasm (½ mark)
  • B = ethanol (½ mark)
  • C = carbon dioxide (½ mark)
  • D = lactic acid (½ mark)
  • E = carbon dioxide (½ mark)
  • F = water (½ 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 paper2026 board paper, set 31/2/1: 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.