A scientist discovers a diseased tomato plant where a disease has caused discolouration in the leaves due to a decrease in chlorophyll. Explain why this tomato plant produces far less tomatoes and is much smaller than a healthy tomato plant.

The decrease in chlorophyll in the diseased plant leaves means the light energy cannot be used to make glucose via photosynthesis in the chloroplasts. Tomatoes store a lot of glucose therefore with less glucose, less tomatoes can be produced. Glucose is also required for respiration which provides energy for plants to grow. Therefore with less glucose the diseased plant will be smaller.