A Level Biology Practice Exam

What is the primary function of xylem in plants?

1. To transport sugars and nutrients

2. To store energy for plant growth

3. To carry water and minerals from the roots

4. To facilitate photosynthesis in leaves

The correct answer is: To carry water and minerals from the roots

The primary function of xylem in plants is to carry water and minerals from the roots to the rest of the plant. Xylem is specialized tissue that forms a part of the vascular system, specifically designed for the conduction of water and essential nutrients absorbed from the soil. This transport process is crucial for maintaining the plant's water balance, supporting photosynthesis, and enabling various physiological processes that sustain plant life. Xylem's structure is well adapted for this role; it consists of hollow tubes made of dead cells that allow for efficient upward movement of water through capillary action and transpiration pull. This system not only facilitates the distribution of water but also helps in transporting soluble minerals necessary for growth and development. Other choices highlight functions related to plant nutrition and energy management, but they pertain more to phloem, which is responsible for transporting sugars made during photosynthesis, energy storage processes, and the facilitation of photosynthesis itself, which occurs primarily in the chloroplasts of leaves rather than within xylem tissue. Thus, the correct answer underscores the vital role of xylem in ensuring plants have the necessary resources for overall growth and development.