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

Which statement describes negative phototropism?

1. It is the growth of shoots towards light

2. It is the growth of roots away from light

3. It is the lack of growth in low light conditions

4. It is the mechanism of leaf bending towards light

The correct answer is: It is the growth of roots away from light

Negative phototropism specifically refers to the manner in which certain plant parts, particularly roots, respond to light by growing away from it. This adaptive behavior is crucial for the plant's survival as it allows roots to seek moisture and nutrients in the soil, which are essential for growth and development. By growing away from light, roots can establish themselves deeper in the ground where these resources are more abundant. In contrast, the other statements pertain to different aspects of plant growth in relation to light. The growth of shoots towards light is known as positive phototropism, while the lack of growth in low light conditions is not specifically referred to as phototropism. The mechanism of leaf bending towards light also describes a positive response, not negative. Therefore, the essence of negative phototropism lies in the growth pattern of roots as they navigate their environment in response to light.