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

Why is a large surface area beneficial for root hair cells?

1. It prevents evaporation of water

2. It allows them to absorb maximum amounts of water and minerals

3. It assists in photosynthesis efficiency

4. It strengthens the cell wall

The correct answer is: It allows them to absorb maximum amounts of water and minerals

A large surface area is beneficial for root hair cells primarily because it allows them to absorb maximum amounts of water and minerals from the soil. Root hair cells are specialized structures that extend from the surface of roots, significantly increasing the area available for absorption. This increased surface area enhances the cell's ability to interact with soil particles and takes advantage of capillary action, which is crucial for nutrient uptake. The more extensive the surface area, the more opportunities there are for the root hairs to come into contact with water molecules and dissolved minerals present in the soil. This efficiency in absorption is vital for the plant’s overall nourishment and growth. Considering the other options, while maintaining water against evaporation is important for plants, it is not the primary function of root hair cells. Photosynthesis occurs mainly in leaves where chlorophyll is present, and root hair cells do not play a direct role in this process. Additionally, while cell wall strength can be important for overall plant structure, it does not relate to the function of root hair cells in terms of surface area and absorption.