Science — CBSE Class 10 board question

Proteins are responsible for expressing traits in an organism. For example, tallness in plants is controlled by a specific protein — the enzyme that produces the plant hormone gibberellin. If the gene for this enzyme is present and functional, gibberellin is produced, the plant grows tall. If the gene is absent or non-functional, the enzyme (protein) is not made, gibberellin is not produced, and the plant remains short (dwarf).

Thus, genes control traits by directing the synthesis of specific proteins.

This question links genetics (Chapter 8) to biochemistry. The key idea is the gene → protein → trait pathway. Examiners expect students to:

1. State that genes control protein synthesis.
2. Give the specific example: gene → enzyme → gibberellin → tallness.
3. Show the consequence when the gene/protein is absent (dwarf plant).

Avoid vague statements like "genes determine height" without explaining the protein link.