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

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Study for the OCR GCSE Biology Exam. Use multiple choice questions and quiz flashcards with explanations and hints. Excel in your exams!

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Why do stomata open during the day?

To allow heat to escape
To maximize carbon uptake for photosynthesis
To absorb more water
To prevent wilting of the plant

The correct answer is: To maximize carbon uptake for photosynthesis

Stomata open during the day primarily to maximize carbon uptake for photosynthesis. During daylight, plants require carbon dioxide, which they absorb through the stomata, to facilitate the photosynthetic process. This process converts light energy into chemical energy, allowing plants to produce glucose and oxygen. The opening of the stomata permits a higher influx of carbon dioxide from the atmosphere, which is essential for efficient photosynthesis. While stomata do help in regulating water loss and can play a role in temperature control by allowing water vapor to escape, these are not the primary reasons for their opening during daylight. The focus during the day is on achieving the necessary conditions for photosynthesis, making the enhancement of carbon dioxide intake the key reason for stomatal opening.