GCSE Biology: Plant Tissues and Transport

Plants get their own organisation questions at GCSE, and they hinge on one comparison every student must have cold: xylem versus phloem. This quiz covers plant tissues and transport from leaf anatomy to the factors driving transpiration.

The tissue questions map the leaf layer by layer: the waxy cuticle preventing water loss, the palisade mesophyll packed with chloroplasts as the main photosynthetic layer, and the spongy mesophyll whose air spaces exist for gas diffusion. The transport comparison is tested from both sides: xylem as dead, hollow, lignin-reinforced vessels carrying water and minerals upwards only, and phloem carrying dissolved sugars — translocation, from sources to sinks — in both directions. Root hair cells appear with their absorption adaptations: large surface area and thin walls.

Transpiration forms the second half. The multi-select question on rate factors requires knowing that temperature, light intensity and wind speed all increase the rate — while increased humidity, the tempting fourth option, actually decreases it by shrinking the water vapour concentration gradient. A dedicated follow-up question tests that humidity relationship directly, and the stomata questions explain both the mechanism (guard cells opening and closing the pores) and the evolutionary logic of why most stomata sit on the cooler, shaded lower surface of the leaf.

Every question is self-contained, and the explanations consistently give the gradient-based reasoning rather than bare facts — the difference between a memorised answer and one that survives an unfamiliar exam context. Pairs naturally with the Photosynthesis quiz in this collection.

• Identify leaf tissues and their functions, from cuticle to spongy mesophyll
• Contrast xylem and phloem in structure, contents and direction of transport
• Explain transpiration and how temperature, light, wind and humidity each affect its rate
• Describe root hair cell adaptations for absorption
• Explain how stomata and guard cells balance gas exchange against water loss

Topic scope follows the organisation section of the Department for Education's GCSE combined science subject content: plant tissues and their organisation into organs, xylem and phloem transport, transpiration and the factors affecting it.