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(a) Draw a labelled diagram… (Class 10 Science 2026, Q16A)

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ScienceCBSE Class 10 · Board exam 2026, set 31/4/1 · 5 marks · Long answer

CBSE Class 10 Science 2026: question 16(A)

Set in the CBSE Class 10 board exam of 2026, paper 31/4/1, section A, question 16(A), for 5 marks. Try it first; the hints and our step-by-step solution are below.

Q16(A) · 5 marks · Long answerLife Processes

(a) Draw a labelled diagram showing open and closed stomatal pore.
(b) List the main events that occur during the process of photosynthesis.
(c) Write a balanced chemical equation showing photo-synthesis in plants.

Figure in the paper: Labelled diagram required showing a stomatal pore in open and closed states, with guard cells marked. See it in the official paper.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2026 board paper, set 31/4/1.

Hints

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

Hint 1

The pore opens or closes depending on whether the guard cells are swollen with water or not.

Hint 2

Think of three stages: capturing light, splitting water, and making sugar from CO.

Hint 3

Glucose is . Balance the carbon atoms first, then oxygen and hydrogen.

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) Open stomatal pore (diagram described): Two bean- or kidney-shaped guard cells are swollen (turgid) and curved outwards, leaving a wide gap between them. Labels: guard cells, stomatal pore (open), chloroplasts, nucleus, epidermal cells. Guard cells take in water and swell, so the pore opens.

    1 mark

  2. Closed stomatal pore (diagram described): Two guard cells are shrunken (flaccid) and lie close together, so the pore is a thin closed slit. Labels: guard cells, stomatal pore (closed), chloroplasts, nucleus, epidermal cells. Guard cells lose water and shrink, so the pore closes.

    1 mark

  3. (b) Main events of photosynthesis:
    1. Chlorophyll absorbs light energy.
    2. Light energy is converted into chemical energy, and water molecules split into hydrogen and oxygen.
    3. Carbon dioxide is reduced to carbohydrates.

    2 marks

  4. (c) Balanced equation:

    1 mark

Answer: (a) Diagrams of open (turgid guard cells) and closed (flaccid guard cells) stomata. (b) Light absorbed by chlorophyll; light energy converted to chemical energy and water split; CO reduced to carbohydrate. (c) (in sunlight, with chlorophyll).

Where the marks are

  • Draws the open stomatal pore with guard cells labelled (1 mark)
  • Draws the closed stomatal pore with guard cells labelled (1 mark)
  • Lists the three events of photosynthesis (2 marks)
  • Writes the balanced equation with sunlight and chlorophyll shown (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 paper2026 board paper, set 31/4/1: 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.