Formative Practice 5.2 (Form 5 Biology Textbook Exercise and Answer)

Question 1:
Name three examples of phytohormones and state their functions.

Three phytohormones and their functions:
• Auxin stimulates cell growth and elongation in roots and shoots.
• Ethylene stimulates ripening in fruits.
• Gibberellin stimulates the division and elongation in the stem cells.

Question 2:
How does auxin control shoot phototropism in the dark?

In the dark, the auxin distribution at the shoot tip is even. The shoot will thus grow straight upwards.

Question 3:
Mr. Farid who sells apples at a supermarket usually separates apples that are too ripe from those that are ripe.
Justify his action.

Fruit that is overripe will produce more ethylene gas. This gas will cause the other fruits to ripe and spoil quickly.

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