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

What is a key consequence of transpiration in plants?

1. Increased water retention

2. Breaking down nutrients

3. Creation of turgor pressure

4. Reduction of photosynthesis

The correct answer is: Creation of turgor pressure

Transpiration is a crucial process in plants that involves the movement of water from the roots to the leaves and its subsequent evaporation from stomata in the leaf surface. One of the primary consequences of transpiration is the creation of turgor pressure. Turgor pressure is the pressure exerted by the fluid (primarily water) inside the vacuoles of plant cells against the cell wall. When water is lost through transpiration, it creates a negative pressure in the xylem vessels, which helps draw more water up from the roots. This upward movement of water not only maintains turgor pressure, enabling the plant to remain rigid and upright but also facilitates the transport of minerals and nutrients dissolved in the water. Turgor pressure is vital for various plant functions, including growth, structure, and cell expansion, making it essential for the overall health and stability of the plant. In contrast, options emphasizing increased water retention, breaking down nutrients, or a reduction of photosynthesis do not accurately reflect the primary significance of transpiration, as transpiration involves water loss, does not directly concern nutrient breakdown, and can actually enhance photosynthesis by ensuring a continuous supply of water and nutrients to the leaves.