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

Which of the following statements is true about transpiration?

1. It is primarily beneficial for cooling the plant

2. It occurs without gas exchange

3. It only occurs in aquatic plants

4. It prevents photosynthesis

The correct answer is: It is primarily beneficial for cooling the plant

Transpiration is the process by which water vapor is released from the interior of a plant to the atmosphere, primarily through small openings called stomata located on the leaves. One of its key benefits is that it helps regulate the temperature of the plant. As water evaporates through these stomata, it cools the plant, much like how sweating cools the human body. This cooling effect is essential for maintaining optimal conditions for physiological processes, including photosynthesis. Other aspects of transpiration include the movement of nutrients and water from the roots to the leaves, which are also facilitated by the transpiration stream. The role of transpiration in gas exchange is important, as it usually accompanies the uptake of carbon dioxide, necessary for photosynthesis, which means it does not occur without gas exchange. Furthermore, transpiration is not limited to aquatic plants—terrestrial plants also experience significant transpiration. Lastly, transpiration does not prevent photosynthesis; rather, it supports it by regulating temperature and enabling the uptake of carbon dioxide through stomata. Thus, the statement regarding transpiration's benefit for cooling the plant accurately reflects an important aspect of the process.