TheLucidSTEM‹ Biology simulationsBiology · AS Level 9700 · 7 Transport in plants
9700 AS Level Biology/Topic 7 Transport in plants/7 interactive simulations/drag to rotate the 3D models

Transport in plants, made interactive

Seven 3D simulations covering Topic 7.1 Structure of transport tissues and 7.2 Transport mechanisms. Explore sections and cells, follow water across the root and up the xylem, and watch sucrose loaded into the phloem and carried by mass flow.

1. Xylem and phloem in sections 3D · 7.1

Transverse sections of a herbaceous dicotyledonous root, stem and leaf, shown as 3D plan diagrams. Click the tissues and compare where the vascular tissue lies.

click a tissue · drag to rotate · wheel to zoom

Organ

2. Xylem vessels, sieve tubes and companion cells 3D · 7.1

The structure of each cell type is related to its function. Click the features of these cut-away cells.

click a feature · drag to rotate · wheel to zoom

Feature

3. Apoplast and symplast pathways 3D · 7.2

Water crosses the root cortex through cell walls (apoplast) or through cytoplasm and plasmodesmata (symplast). At the endodermis the Casparian strip blocks the apoplast.

drag to rotate · wheel to zoom

Pathway

4. Transpiration 3D · 7.2

Water evaporates from the surfaces of mesophyll cell walls into the air spaces, then water vapour diffuses out through the stomata. Change the conditions outside the leaf.

drag to rotate · wheel to zoom

Conditions

TRANSPIRATION RATE

5. Cohesion-tension in the xylem 3D · 7.2

Water molecules are held together by hydrogen bonds (cohesion) and to the cellulose of the walls (adhesion). Transpiration pulls the column up under tension. Then break the column.

drag to rotate · wheel to zoom

Xylem vessel

6. Xerophytic leaves 3D · 7.2

Xerophytes have leaves adapted to reduce water loss by transpiration. Compare a marram grass leaf with an ordinary leaf and click the adaptations.

click a feature · drag to rotate · wheel to zoom

Leaf

7. Loading the phloem and mass flow 3D · 7.2

Companion cells load sucrose into sieve tubes using proton pumps and cotransporters. Water follows by osmosis, building a hydrostatic pressure that drives mass flow from source to sink.

drag to rotate · wheel to zoom

Translocation

PRESSURE AT SOURCE
FLOW TO SINK
Built for Cambridge AS & A Level Biology 9700, Topic 7. Tissues and cells are simplified and not to scale.

About this lab: Transport in plants

Seven interactive 3D simulations for Cambridge AS Level Biology 9700 topic 7 Transport in plants: transverse sections of a dicotyledonous root, stem and leaf showing xylem and phloem, xylem vessel elements, sieve tube elements and companion cells, the apoplast and symplast pathways with the Casparian strip, transpiration and the factors affecting it, cohesion-tension and adhesion in the xylem, xerophytic marram grass leaves, and phloem loading by proton pumps and cotransporters with mass flow from source to sink.

Seven 3D simulations covering Topic 7.1 Structure of transport tissues and 7.2 Transport mechanisms. Explore sections and cells, follow water across the root and up the xylem, and watch sucrose loaded into the phloem and carried by mass flow.

Transport in plants is a free, browser-based simulation for Cambridge International AS & A Level Biology 9700 (topic 7 Transport in plants). The course is assessed in Paper 1 (Multiple choice), Paper 2 (AS structured), Paper 3 (Advanced practical), Paper 4 (A Level structured), Paper 5 (Planning, analysis, evaluation). Syllabus for examination in 2025-2027. There are 7 tabs, each a self-contained experiment with its own controls and live readings, and nothing to install: it runs on a laptop, tablet or classroom projector.

Syllabus coverage

Full syllabus map: AS Level Biology 9700 topic 7.

How to use this simulation

  1. 1. Xylem and phloem in sections. Transverse sections of a herbaceous dicotyledonous root, stem and leaf, shown as 3D plan diagrams.
  2. 2. Xylem vessels, sieve tubes and companion cells. The structure of each cell type is related to its function.
  3. 3. Apoplast and symplast pathways. Water crosses the root cortex through cell walls (apoplast) or through cytoplasm and plasmodesmata (symplast).
  4. 4. Transpiration. Water evaporates from the surfaces of mesophyll cell walls into the air spaces, then water vapour diffuses out through...
  5. 5. Cohesion-tension in the xylem. Water molecules are held together by hydrogen bonds (cohesion) and to the cellulose of the walls (adhesion).
  6. 6. Xerophytic leaves. Xerophytes have leaves adapted to reduce water loss by transpiration.
  7. 7. Loading the phloem and mass flow. Companion cells load sucrose into sieve tubes using proton pumps and cotransporters.
  8. The buttons at the end of the tab strip give the scene the whole window (Full screen, Hide controls) and, on a dark stage, a projector-friendly palette (Light scene). Many scenes also have drag handles: drag them to change the set-up directly.

All simulation labs · AS Level Biology 9700 · TheLucidSTEM home