Which leaf layer contains more organelles for photosynthesis?

Which leaf layer contains more organelles for photosynthesis?

• A. Palisade layer
• B. Spongy mesophyll
• C. Lower epidermis
• D. Vascular bundle

Answer: (A)

Photosynthesis happens where there are lots of chloroplasts. The palisade mesophyll sits just below the upper surface of the leaf and is made up of tall, tightly packed cells filled with chloroplasts. That high chloroplast density, combined with the cells being arranged to intercept a lot of light, makes this layer the main site for photosynthesis. The spongy mesophyll contains some chloroplasts but has more air spaces, so it’s less dense in chloroplasts and receives light more diffusely. The lower epidermis mainly serves protection and gas exchange, with far fewer chloroplasts. The vascular bundle is for transport (xylem and phloem) and isn’t a major photosynthetic tissue. So the palisade layer has the most organelles dedicated to photosynthesis.

Photosynthesis happens where there are lots of chloroplasts. The palisade mesophyll sits just below the upper surface of the leaf and is made up of tall, tightly packed cells filled with chloroplasts. That high chloroplast density, combined with the cells being arranged to intercept a lot of light, makes this layer the main site for photosynthesis. The spongy mesophyll contains some chloroplasts but has more air spaces, so it’s less dense in chloroplasts and receives light more diffusely. The lower epidermis mainly serves protection and gas exchange, with far fewer chloroplasts. The vascular bundle is for transport (xylem and phloem) and isn’t a major photosynthetic tissue. So the palisade layer has the most organelles dedicated to photosynthesis.