A Level Biology Practice Exam

What describes the role of palisade cells in leaves?

1. They assist in water transportation

2. They are primarily for structural support

3. They are closely packed for photosynthesis

4. They store nutrients for the plant

The correct answer is: They are closely packed for photosynthesis

Palisade cells play a crucial role in photosynthesis, which is the process by which plants convert light energy into chemical energy. These cells are located just beneath the upper epidermis of the leaf and are characterized by their cylindrical shape and close packing. This arrangement maximizes light absorption; being densely packed allows them to capture as much sunlight as possible, which is essential for the chloroplasts within them to efficiently perform photosynthesis. In addition to their arrangement, palisade cells contain a high concentration of chloroplasts, the organelles responsible for capturing light energy. The close proximity of these cells to the leaf surface also facilitates gas exchange, allowing carbon dioxide to diffuse into the cells where it can be used in photosynthesis. Thus, their primary function aligns tightly with optimizing the process of photosynthesis, making them integral to a plant's ability to produce energy.