The unit in one line
How a plant moves water, makes food from light, releases energy from that food, and controls its own growth. 6 of Botany's 40 questions over four chapters, with small numericals (DPD, ATP counts, RQ) mixed in.
Read in this order
- Water relations (9 min) — diffusion, osmosis and the DPD and water-potential relations, plasmolysis, absorption, the ascent of sap, transpiration and the stomatal mechanism.
- Photosynthesis (9 min) — pigments, the two photosystems and the Z-scheme, the Calvin cycle, the C4 pathway, photorespiration and the limiting factors.
- Respiration (8 min) — glycolysis, the link reaction, the Krebs cycle, the electron transport system and the ATP tally, anaerobic respiration and RQ. Read after photosynthesis: the two are best learnt as mirror images.
- Plant growth (7 min) — auxins, gibberellins and cytokinins with their uses, seed germination and dormancy.
About 35 minutes in all. The cell organelles behind these processes (chloroplast, mitochondrion) are in Cell organelles.
How it is asked
MEC sets the paper roughly half recall, a third understanding and a fifth application. Recall here is reaction-centre wavelengths, the first stable product of each pathway, and which hormone does what. Understanding is why C4 plants do not photorespire, or why water moves from one cell to another. Application is a DPD problem between two cells, an RQ to calculate, or a described experiment (a bolting rosette, a bent coleoptile) to explain.
Then practise
Each chapter has a fixed-length chapter test under Practice › Topics, drawn from questions written to that chapter's scope. Sit it after reading; a second sitting a week later shows whether it stuck.