Question

Which of the following describes how carbon dioxide enters into a plant?

1) Through the stomata in the leaves
2) Through the roots
3) Through the flowers
4) Through the stem

Answer 1

Carbon dioxide enters plants through stomata in the leaves, which are regulated by guard cells. Once inside, it diffuses to the mesophyll cells and into the chloroplast for the Calvin cycle of photosynthesis.

Step-by-step explanation:

In plants, carbon dioxide (CO₂) enters through the stomata in the leaves. The stomata are small openings that are regulated by guard cells, which control their opening and closing. This process not only allows carbon dioxide to enter for photosynthesis but also plays a crucial role in transpiration, which is the movement of water within the plant and its evaporation from leaves, stems, and flowers. Carbon dioxide enters the leaf, diffuses through intercellular spaces until it reaches the mesophyll cells, and then moves into the stroma of the chloroplast, where the Calvin cycle (the light-independent reactions of photosynthesis) takes place.