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9700 A Level Biology/Topic 13 Photosynthesis/8 interactive simulations/drag to rotate the 3D models

Photosynthesis, made interactive

Eight 3D simulations covering Topic 13.1 Photosynthesis as an energy transfer process and 13.2 Investigation of limiting factors. Explore a chloroplast, shine coloured light on pigments, run a chromatogram, drive electrons through the photosystems, turn the Calvin cycle and investigate limiting factors.

1. The chloroplast 3D · 13.1

The thylakoids, stacked into grana, are the site of the light-dependent stage; the stroma is the site of the light-independent stage (Calvin cycle). Click the structures.

click a part · drag to rotate · wheel to zoom

Structure

2. Pigments and spectra 3D · 13.1

Chlorophyll a, chlorophyll b, carotene and xanthophyll absorb different wavelengths. Shine light of one colour on the antenna complex and compare the absorption and action spectra.

drag to rotate · wheel to zoom

Wavelength

3. Chromatography of pigments 3D · 13.1

A spot of leaf extract is placed on the origin line and the solvent rises through the paper, separating the pigments. Run it, then click each spot to find its Rf value.

click a spot · drag to rotate · wheel to zoom

Chromatogram

PIGMENT
-
Rf
-

4. The light-dependent stage 3D · 13.1

On the thylakoid membrane, light excites electrons in the photosystems. Compare non-cyclic and cyclic photophosphorylation.

drag to rotate · wheel to zoom

Pathway

ATP
0
REDUCED NADP
0
O₂
0

5. The Calvin cycle 3D · 13.1

In the stroma, rubisco fixes carbon dioxide; ATP and reduced NADP from the light-dependent stage are used to make triose phosphate. Follow three turns of the cycle.

drag to rotate · wheel to zoom

Stage

6. Limiting factors 3D · 13.2

The rate of photosynthesis is limited by whichever factor is in shortest supply. Change light intensity, carbon dioxide and temperature.

drag to rotate · wheel to zoom

Factors

RATE
LIMITING FACTOR

7. DCPIP and isolated chloroplasts 3D · 13.2

Chloroplasts in buffer reduce blue DCPIP to colourless when light drives the light-dependent stage. Compare light intensities or colours of light.

drag to rotate · wheel to zoom

Variable

tubelighttime to decolourise

8. Investigating with pondweed 3D · 13.2

Count the oxygen bubbles given off by an aquatic plant. Move the lamp, change the hydrogencarbonate concentration or the temperature of the water bath, and record the rate.

drag to rotate · wheel to zoom

Set-up

distance1/d² (×10⁻³)NaHCO₃°Cbubbles/min
Built for Cambridge AS & A Level Biology 9700, Topic 13 (A Level). Spectra, Rf values and rates are typical values; models are simplified and not to scale.

About this lab: Photosynthesis

Eight interactive 3D simulations for Cambridge A Level Biology 9700 topic 13 Photosynthesis: chloroplast structure with grana, thylakoids and stroma, absorption spectra of chlorophyll a, chlorophyll b, carotene and xanthophyll with the action spectrum, chromatography of pigments with Rf values, cyclic and non-cyclic photophosphorylation with photolysis and chemiosmosis, the Calvin cycle with rubisco, RuBP, GP and TP, limiting factors, DCPIP with isolated chloroplasts, and investigating pondweed.

Eight 3D simulations covering Topic 13.1 Photosynthesis as an energy transfer process and 13.2 Investigation of limiting factors. Explore a chloroplast, shine coloured light on pigments, run a chromatogram, drive electrons through the photosystems, turn the Calvin cycle and investigate limiting factors.

Photosynthesis is a free, browser-based simulation for Cambridge International AS & A Level Biology 9700 (topic 13 Photosynthesis). 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 8 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: A Level Biology 9700 topic 13.

How to use this simulation

  1. 1. The chloroplast. The thylakoids, stacked into grana, are the site of the light-dependent stage; the stroma is the site of the...
  2. 2. Pigments and spectra. Chlorophyll a, chlorophyll b, carotene and xanthophyll absorb different wavelengths.
  3. 3. Chromatography of pigments. A spot of leaf extract is placed on the origin line and the solvent rises through the paper, separating the pigments.
  4. 4. The light-dependent stage. On the thylakoid membrane, light excites electrons in the photosystems.
  5. 5. The Calvin cycle. In the stroma, rubisco fixes carbon dioxide; ATP and reduced NADP from the light-dependent stage are used to make...
  6. 6. Limiting factors. The rate of photosynthesis is limited by whichever factor is in shortest supply.
  7. 7. DCPIP and isolated chloroplasts. Chloroplasts in buffer reduce blue DCPIP to colourless when light drives the light-dependent stage.
  8. 8. Investigating with pondweed. Count the oxygen bubbles given off by an aquatic plant.
  9. 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.

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