GCSE Year 10 Combined Science Biology AQA - Plant tissues and transport

Leaf Organ

Contains epidermis, palisade mesophyll, spongy mesophyll, xylem, phloem, guard cells and stomata.

Palisade mesophyll

Packed with chloroplasts for photosynthesis.

Spongy mesophyll

Air spaces allow gas diffusion.

Epidermal tissue

Cover and protects leaf

Root hair cells

Large surface area for water uptake by osmosis and mineral ion uptake by active transport.

Xylem

Hollow lignified tubes transport water and mineral ions from roots to leaves.

Phloem

Transports dissolved sugars from leaves to rest of plant by translocation.

Stomata and guard cells

Control gas exchange and water loss.

Transpiration

Loss of water vapour from leaves; affected by temperature, humidity, air movement and light intensity.

Translocation

Movement of dissolved sugars through phloem.