# Transport in Plants

> CIE IGCSE Biology · CIE IGCSE Biology (0610)
> Source: https://www.owlsprep.com/study/cie-0610-u6-overview/
> Weight: 8-10% of Paper 1/2 MCQ, 12-15% of structured questions in Paper 3/4

This unit covers specialized transport tissues in flowering plants, mechanisms of water and mineral uptake, transpiration, and (for extended candidates) the movement of organic nutrients via translocation.

**Prerequisites:** [Cell structure and organisation (Unit 2)](https://www.owlsprep.com/study/cie-0610-u2-overview/); [Diffusion, osmosis and active transport (Unit 3)](https://www.owlsprep.com/study/cie-0610-u3-overview/)

## Learning objectives

- Distinguish between the structure and function of xylem and phloem tissues
- Explain mechanisms of water and mineral uptake by roots and transpiration flow up the xylem
- Analyse factors that affect transpiration rate and interpret potometer experimental data
- (Extended only) Describe the active process of translocation of organic solutes in phloem

## Unit at a Glance

The unit opens with a comparison of the two key vascular tissues in plants: xylem and phloem. It then explores how water and minerals move from root hair cells, through the root cortex, up the xylem to the leaves, and is lost as water vapor via transpiration, including practical skills for measuring transpiration rates with a potometer.

Core candidates complete their learning for this unit after mastering transpiration, while extended candidates proceed to study translocation: the active, bidirectional transport of dissolved sugars and amino acids around the plant body via phloem tissue.

Navigate to the sub-topics below to begin your learning:
- [Xylem, Phloem, Water Uptake and Transpiration](https://www.owlsprep.com/study/cie-0610-u6-xylem-phloem-water-uptake-and/) — Covers vascular tissue structure, root hair cell adaptations, transpiration mechanism, factors affecting transpiration rate, and potometer practical skills for core and extended candidates.
- [Translocation (Extended Only)](https://www.owlsprep.com/study/cie-0610-u6-translocation/) — Extended-only content covering the active mechanism of translocation in phloem, including sources and sinks of organic solutes in the plant.

## Common pitfalls

- **Wrong:** Confusing xylem and phloem transport direction and substance types
  - Why it fails: Both are vascular tissues but have opposite transport directions and carry different materials, a very common MCQ mistake
  - Correct: Remember: xylem carries water/minerals *up only*; phloem carries sugars *up and down* the plant
- **Wrong:** Assuming transpiration is an active, energy-requiring process
  - Why it fails: Many students mix up passive transpiration flow with active translocation
  - Correct: Transpiration is a passive process driven by evaporation of water from leaf surfaces: no ATP is required
- **Wrong:** Using transpiration and translocation interchangeably in responses
  - Why it fails: The terms sound similar and both relate to plant transport, leading to lost marks in structured questions
  - Correct: Label clearly: transpiration = water movement via xylem; translocation = sugar movement via phloem (extended only)

## Cheatsheet

| Concept | Key Detail | Associated Tissue |
| --- | --- | --- |
| Xylem function | Transport water + dissolved mineral ions from roots to shoots, provide structural support | Xylem |
| Phloem function | Transport dissolved sucrose and amino acids to all parts of the plant | Phloem |
| Transpiration definition | Loss of water vapor from plant leaves via evaporation and diffusion out of stomata | Xylem |
| Transpiration rate drivers | Increased by high temperature, wind, light intensity; decreased by high humidity | Xylem |
| Translocation (Extended) | Active movement of organic solutes from sources (e.g. leaves) to sinks (e.g. roots, fruits) | Phloem |
| Root hair adaptation | Large surface area to maximise osmosis of water and active transport of minerals | Root epidermis |

## What's next

Start your study of plant transport with the first core sub-topic: Xylem, Phloem, Water Uptake and Transpiration, which covers all assessment content for core candidates, and foundational content for extended candidates. If you are sitting the extended exam, move on to the Translocation sub-topic once you have mastered the core content. After completing this unit, you will progress to the next unit on transport in humans.

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From [OwlsPrep](https://www.owlsprep.com) — free study guides for A-Level, IB, AP and IGCSE, written against the official syllabus. Canonical page: https://www.owlsprep.com/study/cie-0610-u6-overview/