OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

What is the role of plant hormones in growth regulation?

1. They directly cause photosynthesis

2. They control various growth processes

3. They prevent any form of growth

4. They destroy old plant tissues

The correct answer is: They control various growth processes

Plant hormones, also known as phytohormones, play a crucial role in the regulation of growth processes in plants. They are chemical signaling molecules produced in one part of the plant that can influence growth and development in another part. These hormones help coordinate various aspects of growth such as cell division, elongation, and differentiation, thereby facilitating processes like stem growth, root growth, flowering, and fruit development. Different types of plant hormones are responsible for different functions. For example, auxins promote stem elongation and inhibit the growth of lateral buds, leading to apical dominance. Gibberellins stimulate seed germination and stem elongation, while cytokinins promote cell division and prevent aging in leaves. Ethylene influences fruit ripening and abscission. By regulating these processes, plant hormones ensure that a plant can respond appropriately to environmental changes and developmental cues, ultimately supporting its growth and survival. In contrast, the other options do not accurately represent the role of plant hormones. While plants do engage in photosynthesis, hormones do not directly cause this process. Plant hormones also do not prevent all forms of growth; instead, they fine-tune growth according to the plant's needs. Furthermore, while some hormones can trigger the breakdown of certain tissues