A Level Biology Practice Exam

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Master the A Level Biology Exam. Use flashcards and multiple choice questions with hints and explanations to ace your test. Start your journey to excellence!

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Which of the following is NOT a function of guard cells?

Opening stomatal pores
Controlling water loss
Carrying nutrients
Regulating gas exchange

The correct answer is: Carrying nutrients

Guard cells primarily function to regulate the opening and closing of stomatal pores, which are essential for gas exchange and controlling water loss in plants. They are specialized cells that respond to environmental conditions, allowing the stomata to open or close accordingly. By doing so, guard cells facilitate the uptake of carbon dioxide for photosynthesis while minimizing excessive water loss through transpiration. In addition to their role in gas exchange, guard cells play a critical part in regulating water loss, helping the plant maintain hydration and overall health. They do not, however, carry nutrients. Nutrient transport in plants is primarily handled by other types of cells and systems, such as the xylem and phloem, which are responsible for transporting water, minerals, and organic compounds throughout the plant. Therefore, the statement that guard cells carry nutrients is inaccurate, making it the correct choice for the answer to the question posed.