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"Proteins control the… (Class 10 Science 2025, Q23a)

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ScienceCBSE Class 10 · Board exam 2025, set 31/6/1 · 2 marks · Very short answer

CBSE Class 10 Science 2025: question 23(a)

Set in the CBSE Class 10 board exam of 2025, paper 31/6/1, 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 answerHeredity

"Proteins control the expression of various characters." Explain this statement by taking an example of "tallness" as a characteristic in plants.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2025 board paper, set 31/6/1.

Hints

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

Hint 1

Plant height depends on a growth hormone. What kind of molecule helps make that hormone?

Hint 2

Follow the chain gene → protein (enzyme) → hormone → height.

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. The height of a plant depends on the amount of a particular plant growth hormone it makes. This hormone is produced with the help of an enzyme, which is a protein. The enzyme is made according to the information in a gene, which is a section of DNA.

    1 mark

  2. If the gene gives an efficient enzyme, plenty of hormone is made and the plant grows tall. If the gene is altered and the enzyme works less efficiently, less hormone is made and the plant stays short. So proteins (enzymes) control the expression of the character.

    1 mark

Answer: Gene → efficient enzyme (protein) → more growth hormone → tall plant; a less efficient enzyme gives less hormone and a short plant.

Where the marks are

  • Links plant height to the amount of growth hormone, made with the help of an enzyme (protein) coded by a gene (1 mark)
  • Explains that an efficient enzyme gives more hormone and a tall plant, and a less efficient one gives a short plant (1 mark)

Revise the chapter

  • Chapter: Heredity (notes, formulas, where marks are lost and every past question)
Practise this chapterBoard-style questions from Heredity, one at a time, marked against the answer key and marking points.Back to the full paper2025 board paper, set 31/6/1: 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.