Who this is for: Cambridge IGCSE Biology (0610) students who want xylem and phloem — the two vascular tissues in plants — to become reliable marks instead of a confused “xylem carries everything” answer.
What query it owns: how to understand and revise xylem and phloem in Cambridge IGCSE Biology.
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 vascular tissues that transport substances around a plant. Xylem carries water and mineral ions upward from roots; phloem carries sucrose and amino acids to where they are needed. Cambridge IGCSE Biology (0610) tests whether you can compare their structure, state what each transports, and link structure to function. This guide covers the syllabus definitions and the compare questions that appear every year.

Key takeaways

• Xylem transports water and mineral ions upward; vessels are dead with lignified walls.
• Phloem transports sucrose and amino acids (assimilates); sieve tubes are living cells.
• Xylem transport is driven mainly by transpiration; phloem transport is translocation.
• Xylem vessels form a continuous hollow tube — no end walls — for efficient water flow.
• Compare questions need substance, direction and cell state (dead vs living) for both tissues.

What are xylem and phloem in Cambridge IGCSE Biology?

Xylem and phloem are found together in vascular bundles in stems and roots. Xylem vessels are dead, hollow cells with thick lignified walls that resist the suction force of transpiration. They transport water and dissolved mineral ions from roots to leaves. Phloem consists of sieve tubes (living cells with perforated end walls) and companion cells. Phloem transports sucrose and amino acids from sources (e.g. leaves) to sinks (e.g. roots, fruits).

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 function	Water + mineral ions upward	”State what xylem transports”
Phloem function	Sucrose + amino acids to sinks	”State what phloem transports”
Xylem structure	Dead cells, lignin, hollow lumen	”Describe xylem vessel structure”
Phloem structure	Living sieve tubes, sieve plates	”Describe phloem structure”
Compare	Substance, direction, living/dead	”Compare xylem and phloem”

Xylem vs phloem — comparison table

Feature	Xylem	Phloem
Substance transported	Water and mineral ions	Sucrose and amino acids
Direction	Upward (roots → leaves)	Up or down (source → sink)
Cell state	Dead at maturity	Living (sieve tubes)
Wall material	Lignin (thick, strong)	Thin cellulose cell walls
End walls	Absent (continuous tube)	Sieve plates (perforated)
Driving force	Transpiration pull	Translocation (pressure flow)

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

Command word / phrase	What the question wants	Typical xylem/phloem stem
Compare	Similarities and differences	”Compare the structure and function of xylem and phloem.”
Describe	Structure or function in detail	”Describe the structure of a xylem vessel.”
State	Short factual answer	”State what is transported in phloem.”
Explain	Cause and effect	”Explain why xylem vessels have lignified walls.”
Identify	Name from diagram	”Identify tissue A on the transverse section.”

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

1. “Compare xylem and phloem.” Xylem: dead cells, lignified walls, transports water and mineral ions upward. Phloem: living sieve tubes, transports sucrose and amino acids from source to sink in either direction. Mark-scheme reward: substance + direction + living/dead for both.
2. “Describe the structure of xylem vessels.” Dead cells; end walls broken down forming a continuous hollow tube; walls thickened with lignin for strength. Reward: dead + hollow + lignin.
3. “State two substances transported in phloem.” Sucrose and amino acids. Reward: both named — not “food” alone.

When you can recognise the wording instantly, work the full set on the Transport in Plants topical past paper questions and the Xylem and Phloem quiz.

How xylem and phloem connect to the rest of the syllabus

Xylem links to Water Uptake and Transpiration. Phloem links to Translocation. The Cambridge IGCSE Biology resource hub links every Transport in Plants subtopic.

Common mistakes students make

• Saying xylem transports sugar or phloem transports water.
• Describing xylem as living — mature xylem vessels are dead.
• Omitting lignin when describing xylem wall structure.
• Saying phloem only transports upward — direction depends on source and sink.
• Using “food” instead of sucrose and amino acids in phloem answers.

When you need more support

If compare questions keep costing marks, work through the Transport in Plants topical past paper questions and the Xylem and Phloem quiz, then get focused help from a Cambridge IGCSE Biology tutor.

Frequently asked questions

Is xylem and phloem hard in Cambridge IGCSE Biology? The compare table is the main challenge — students mix up substances and directions.

What is the difference between xylem and phloem? Xylem carries water and minerals upward in dead lignified vessels; phloem carries sucrose and amino acids in living sieve tubes to wherever they are needed.

Why are xylem vessels dead? So they form an unobstructed hollow tube for efficient water transport without cytoplasm blocking the lumen.

How do I revise xylem and phloem effectively? Build a compare table from memory, practise structure descriptions, then take the Xylem and Phloem quiz.

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