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

Gibberellin works alongside which other hormone to influence plant growth?

1. Cytokinin

2. Ethene

3. Auxin

4. Abscisic acid

The correct answer is: Auxin

Gibberellin is a plant hormone that promotes growth, particularly in stem elongation and seed germination. It works closely with auxin, which is another key plant hormone that regulates growth and development in various ways, including cell elongation and differentiation. Together, gibberellin and auxin coordinate several physiological processes, such as bud development and the growth of fruits, ensuring that plants respond properly to environmental stimuli and optimize their growth patterns. Cytokinin also plays a role in plant growth but is more focused on promoting cell division and delaying aging in leaves rather than directly working alongside gibberellin. Ethene is primarily involved in the ripening of fruit and managing responses to stress. Abscisic acid has a different function, primarily regulating stress responses and inhibiting growth during unfavorable conditions, making it less directly involved in promoting growth alongside gibberellin. Thus, auxin is the hormone that works in tandem with gibberellin to enhance various aspects of plant growth.