Key Concept: Leaves have specialized tissues that maximize photosynthesis and gas exchange.
Section A: Leaf Structure
1. Label the leaf cross-section with: cuticle, upper epidermis, palisade mesophyll, spongy mesophyll, lower epidermis, stomata, guard cells, xylem, phloem. [9]
[Leaf cross-section diagram]
Section B: Adaptations
2. Describe three adaptations of leaves for photosynthesis. [3]
3. Explain why palisade cells are near the top of the leaf. [2]
4. State the function of stomata and guard cells. [2]
Total marks: 16
Mark Scheme
1. All labels correct [9]
2. Any three: large surface area, thin leaf, many chloroplasts in palisade cells, stomata for gas exchange, air spaces in spongy mesophyll, veins for transport [3]
3. They receive the most light for photosynthesis [2]
4. Stomata allow gas exchange; guard cells control opening/closing to regulate water loss [2]