Fiducia TogetherPlant transport and transpiration
How water and food move through a plant, in two separate systems.
Please note: This page explains a word or a process in education. It is general information about the system, the law and the guidance in England — not advice about your child, your school or your exam. If a decision is going against you, get advice from one of the free services we link to before you agree to anything or miss a deadline. If you are revising, check your own exam board's specification: boards word things differently and yours is the one that marks you.
What it is
Xylem carries water and dissolved minerals upwards from the roots, in dead hollow tubes strengthened with lignin. Phloem carries dissolved sugars in both directions, in living cells, by translocation.
Where it applies
GCSE biology and combined science, with a required practical.
How it works
Transpiration is the loss of water vapour from leaves, mainly through stomata, which pulls water up the xylem. Rate increases with temperature, air movement, light intensity and low humidity.
Guard cells open and close stomata, balancing gas exchange against water loss.
How to use it in your work
Xylem: dead, one direction, water. Phloem: living, both directions, sugars. Learn that pair and most questions follow.
For rate factors, explain the mechanism — higher temperature means faster evaporation and diffusion, not just 'it is hotter'.
A potometer measures water UPTAKE, which is an estimate of transpiration, not the same thing. Saying so is a higher mark.
Where to get help
Your teacher, your board's specification for the depth required at your tier, and Bitesize for the diagrams.
Revise this with a song
These are ours. We write revision songs because a lot of people remember a tune when they cannot remember a page, and because revising out loud in the kitchen beats staring at a highlighter.
- The Biology Song The GCSE biology specification, set to music.
Where to read more
Last reviewed 2026-08-28 by Fiducia Together · Next review due 2027-08-28
Please note: This page explains a word or a process in education. It is general information about the system, the law and the guidance in England — not advice about your child, your school or your exam. If a decision is going against you, get advice from one of the free services we link to before you agree to anything or miss a deadline. If you are revising, check your own exam board's specification: boards word things differently and yours is the one that marks you.