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The breakdown of glucose has… (Class 10 Science 2025, Q12)

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ScienceCBSE Class 10 · Board exam 2025, set 31/1/1 · 1 mark · MCQ

CBSE Class 10 Science 2025: question 12

Set in the CBSE Class 10 board exam of 2025, paper 31/1/1, section A, question 12, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q12 · 1 mark · MCQLife Processes

The breakdown of glucose has taken the following pathway:

The sites 'a' and 'b' respectively are:

  1. (A)Mitochondria and Oxygen deficient muscle cells
  2. (B)Cytoplasm and Oxygen rich muscle cells
  3. (C)Cytoplasm and Yeast cells
  4. (D)Cytoplasm and Oxygen deficient muscle cells

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

Hints

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

Hint 1

Where does the first step of respiration happen?

Hint 2

Which cells make lactic acid, and under what condition?

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. Glucose is broken down to pyruvate (glycolysis) in the cytoplasm of all cells. So site (a) is the cytoplasm.

  2. Pyruvate changes to lactic acid in muscle cells when oxygen is lacking. So site (b) is oxygen-deficient muscle cells. The answer is option (D).

    1 mark

Answer: Cytoplasm and oxygen deficient muscle cells, option (D)

Where the marks are

  • Chooses option (D) (1 mark)

Revise the chapter

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 31/1/1: 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.