A Level Biology Practice Exam

What is the main function of root hair cells?

1. To transport nutrients in the xylem

2. To increase surface area for absorption

3. To perform photosynthesis

4. To provide structural support

The correct answer is: To increase surface area for absorption

The correct answer is focused on the primary role of root hair cells, which is to increase surface area for absorption. Root hair cells are specialized extensions of root epidermal cells that significantly enhance the ability of the plant to absorb water and dissolved nutrients from the soil. This increased surface area allows for more efficient uptake since the root hairs can come into close contact with soil particles and create a larger interface for absorption. Root hair cells do not transport nutrients in the xylem, as that function is performed by specialized xylem vessels. They also do not perform photosynthesis because photosynthesis primarily occurs in the green parts of the plant, such as leaves. Lastly, while root systems do provide structural support, this is not the main function of root hair cells, which are specifically adapted for enhancing nutrient and water uptake.