Who this is for: Cambridge IGCSE Biology (0610) students who can label xylem and phloem on a diagram but still lose marks on structure–function links and compare questions in Transport in Plants papers.
What query it owns: how to understand and revise xylem and phloem in Cambridge IGCSE Biology (0610).
Why this is safe: this page owns the xylem and phloem revision-guide angle, while Tutopiya’s Xylem and Phloem subtopic page owns the learning resource and the free Xylem and Phloem quiz owns the practice.

Xylem and phloem are the two transport tissues tested in almost every Cambridge IGCSE Biology (0610) Transport in Plants question. Whenever a stem asks what xylem carries, how phloem sieve tubes are adapted, or how the two tissues differ — examiners expect precise structural detail and a clear functional link. This guide explains exactly what the syllabus requires, how to handle the question types that actually appear, and where to practise each skill.

Key takeaways

• Xylem transports water and mineral ions upward from roots to leaves; also provides support (lignified walls).
• Phloem transports sucrose and amino acids (assimilates) up and down the plant — translocation.
• Xylem vessels are dead, hollow tubes with lignified walls and no end plates (in mature vessels).
• Phloem includes sieve tube elements (living, perforated sieve plates) and companion cells (provide energy).
• Compare questions need substance transported, direction, cell state (dead vs living) and process name (transpiration pull vs translocation).

What are xylem and phloem in Cambridge IGCSE Biology?

Xylem and phloem are vascular tissues found together in vascular bundles in stems and roots. Xylem carries water and dissolved mineral ions from roots to leaves, mainly driven by transpiration. Phloem carries organic products of photosynthesis — mainly sucrose — from sources (e.g. leaves) to sinks (e.g. roots, fruits, growing tips) in a process called translocation.

You can read the full explanation, diagrams and notes on Tutopiya’s Xylem and Phloem subtopic page before you attempt questions.

The core ideas you must master

Idea	What it means	How the exam uses it
Xylem vessel structure	Dead, lignified, hollow, no cytoplasm	”Describe the structure of a xylem vessel.”
Phloem sieve tube	Living, sieve plates, no nucleus in sieve element	”State the function of companion cells.”
Direction of transport	Xylem: up; Phloem: up and down	”Compare xylem and phloem.”
Position in bundle	Often xylem inside, phloem outside (stem)	“Label a transverse section of a stem.”

Xylem vs phloem: comparison table for exams

Feature	Xylem	Phloem
Substance transported	Water, mineral ions	Sucrose, amino acids
Direction	Upward (roots → leaves)	Up and down (source → sink)
Process	Transpiration stream / transpiration pull	Translocation
Cell state	Dead (hollow vessels)	Living (sieve tubes + companion cells)
Wall material	Lignin — waterproof, strong	Thin cellulose — sieve plates between cells
Other function	Support for the plant	None (transport only)

How to answer xylem and phloem questions — step by step

1. Read the stem — structure, function or compare?
2. For structure — dead/living, wall type, hollow/sieve plates, companion cells.
3. For function — what is transported and in which direction.
4. For compare — use a table with at least four rows (substance, direction, living/dead, process).
5. Link to wider unit — xylem → transpiration; phloem → translocation.
6. Check labels — xylem and phloem positions differ in root vs stem sections.

Test yourself with the free Xylem and Phloem quiz after working through compare stems.

Xylem and phloem in past-paper wording: command words that matter

Command word / phrase	What the question wants	Typical stem
Describe	Structure or appearance	”Describe the structure of xylem vessels.”
Explain	Reason or mechanism	”Explain how lignin helps xylem function.”
State	Short answer	”State what is transported in phloem.”
Compare	Tabular differences	”Compare xylem and phloem.”
Label	Diagram	”Label xylem and phloem on the transverse section.”

Worked exam-style stems (how to answer the wording)

1. “Compare xylem and phloem.” Xylem: water/minerals, upward, dead hollow vessels, lignin, support. Phloem: sucrose/amino acids, up and down, living sieve tubes with companion cells, translocation. Mark-scheme reward: substance + direction + living/dead.
2. “Explain how xylem vessels are adapted to transport water.” Dead cells form continuous hollow tubes → no cytoplasm to block flow; lignified walls prevent collapse and leakage; joined end to end. Reward: hollow + lignin.
3. “State the role of companion cells in phloem.” Provide energy (ATP) for loading sucrose into sieve tubes / maintain sieve tube elements. Reward: energy + loading/translocation link.

When you can recognise the wording instantly, link to Transpiration and Translocation subtopic pages to complete the unit.

How xylem and phloem connect to the rest of Biology (0610)

Xylem links to water uptake in roots and transpiration in leaves. Phloem links to photosynthesis (sucrose source) and storage organs (sinks). Vascular bundles connect to levels of organisation (tissue level). The Cambridge IGCSE Biology resource hub links every Transport in Plants resource.

Common mistakes students make

• Saying phloem transports water — xylem carries water.
• Saying xylem cells are living — mature xylem vessels are dead.
• Forgetting phloem transport is bidirectional (source to sink).
• Omitting companion cells in phloem structure answers.
• Confusing lignin (xylem) with cellulose (general plant cell wall).

When you need more support

If compare questions keep tripping you up, work through the Xylem and Phloem quiz and Water Uptake notes, then get focused help from a Cambridge IGCSE Biology tutor.

Frequently asked questions

Is xylem vs phloem hard in Cambridge IGCSE Biology? The comparison is highly predictable. Marks are lost when students swap substances transported or forget phloem is living.

What is the quickest compare answer for xylem and phloem? Xylem: water/minerals up, dead lignified vessels. Phloem: sucrose up and down, living sieve tubes with companion cells.

Where are xylem and phloem found? In vascular bundles in stems and roots, and in veins of leaves.

How do I revise xylem and phloem effectively? Draw and label both tissues, complete a compare table from memory, then take the Xylem and Phloem quiz.

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