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

What is a key factor that influences chlorophyll production in leaves?

1. Temperature fluctuations

2. Water availability exclusively

3. Daylight hours

4. Nutrient levels in the soil

The correct answer is: Daylight hours

Chlorophyll production in leaves is primarily influenced by the amount of daylight hours, as this directly affects the process of photosynthesis. Chlorophyll is the green pigment found in plants that captures sunlight needed for photosynthesis, allowing plants to convert light energy into chemical energy. During longer daylight hours, plants experience increased light exposure, which stimulates the production of chlorophyll. As a result, optimal light conditions, which can be influenced by the seasons and geographical location, are crucial for the synthesis of chlorophyll. This process is particularly evident during spring and summer when plants are exposed to more light, promoting robust growth and vibrant green leaves. While factors such as temperature fluctuations, water availability, and nutrient levels are important for overall plant health and can indirectly affect chlorophyll production, the primary driver specific to chlorophyll synthesis is the amount of light energy available.