How does carbon dioxide enter a leaf? – CO2 is moved by active transport into the leaf by special cells called guard cells. – CO2 passes through openings called stomata on the leaf surface. – CO2 diffuses through the epidermal cells into the mesophyll. – CO2 travels dissolved in the water in the xylem. – Atmospheric pressure forces CO2 through pits on the leaf surface.

Sourav PanSeptember 5, 2024

Answered

Carbon dioxide (CO₂) primarily enters a leaf through openings called stomata on the leaf surface. Here’s a brief overview of the process:

1. Stomata: CO₂ enters the leaf through tiny openings on the leaf surface called stomata. These are regulated by guard cells that control the size of the stomatal openings.
2. Diffusion: Once inside the leaf, CO₂ diffuses through the intercellular spaces and moves into the mesophyll cells, where photosynthesis occurs.
3. Guard Cells: Guard cells around the stomata help regulate gas exchange by opening and closing the stomata, thus controlling the entry of CO₂ and the release of oxygen.

The other options mentioned are not accurate for the primary movement of CO₂ into the leaf:

• Active Transport: CO₂ does not require active transport to enter the leaf; it moves passively via diffusion.
• Epidermal Cells: CO₂ doesn’t typically diffuse through the epidermal cells into the mesophyll; it moves directly through the stomata.
• Xylem: CO₂ does not travel dissolved in the water in the xylem; the xylem primarily transports water and minerals.
• Atmospheric Pressure: While atmospheric pressure influences gas exchange, it does not force CO₂ through pits. The stomata are the main structures for gas exchange.