GCSE›Edexcel GCSE Biology›Mind mapsPlant StructureEdexcel GCSE Biology: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsRoot hair cellLong extension gives large surface areaLarge vacuole helps osmosisMany mitochondria for active transportWater enters by osmosis, ions by active transportXylemDead, lignified cells forming hollow tubesCarries water and minerals upwards onlyLignin strengthens the wallsPhloemLiving sieve tube elements with sieve platesCompanion cells supply energyCarries sucrose in both directionsMovement of sugars is translocationPlant structurecells and tissuesLeaf structurePalisade mesophyll: many chloroplasts, near topSpongy mesophyll: air spaces for gas diffusionStomata: gas exchange pores, mostly lower surfaceGuard cells open and close stomataDry habitatsSmall or needle-like leavesThick waxy cuticleFewer, sunken stomataStomata closed in the dayAll reduce water lossExam tipsXylem: dead, one-way. Phloem: living, two-wayDo not mix up osmosis and active transportLink each adaptation to its function