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

What is the function of root hairs in plants?

1. To anchor the plant to the soil

2. To increase surface area for water and mineral absorption

3. To synthesize food

4. To protect the roots from disease

The correct answer is: To increase surface area for water and mineral absorption

Root hairs are specialized structures that emerge from the roots of plants, primarily serving the critical function of increasing the surface area available for water and mineral absorption. This is essential for the plant's overall health and growth, as water and nutrients are vital for various physiological processes. The extensive network of root hairs allows for more efficient uptake of essential nutrients from the soil, enhancing the plant's ability to sustain itself, particularly in environments where nutrient availability may be limited. The larger surface area provided by root hairs creates more contact points with the soil, facilitating greater absorption efficiency. While anchoring the plant to the soil, synthesizing food, and protecting roots from disease are important functions, they are not the primary role of root hairs. Instead, these hairs fundamentally contribute to the plant’s nutritional needs by maximizing the amount of water and minerals that can be absorbed from the surrounding soil.