A Level Biology Practice Exam

In what type of cells are chloroplasts primarily found?

1. Parenchyma cells in leaves

2. Phloem cells in roots

3. Xylem cells in stems

4. Sclerenchyma cells in seeds

The correct answer is: Parenchyma cells in leaves

Chloroplasts are primarily found in parenchyma cells, specifically in the mesophyll of leaves. These cells are crucial for photosynthesis, the process by which plants convert light energy into chemical energy stored in glucose. The presence of chloroplasts within parenchyma cells allows for efficient capture of sunlight, facilitating the absorption of carbon dioxide and the release of oxygen, both of which are vital to the overall process of photosynthesis. In contrast, phloem cells, which transport sugars and other organic nutrients throughout the plant, do not contain chloroplasts as their main function is not photosynthesis. Similarly, xylem cells, which are responsible for water and mineral transport from roots to other parts of the plant, also lack chloroplasts since their primary role is structural support and transportation. Lastly, sclerenchyma cells provide structural support and protection, particularly in seeds and are typically dead at maturity, thus do not have chloroplasts either. This distinction emphasizes the specialized roles of various cell types in plant physiology, highlighting the unique function of parenchyma cells in photosynthesis and the presence of chloroplasts.