PSLE Science — Life Science Revision (Concept Map)

PSLE Science — Final Revision

Life Science · the topics that came up in every paper, and how they were asked

Most-tested life topics, 2023–2025: plant reproduction 11 questions, plant water and food 9, cells and classification 6 each.

All of them appeared in 2023, 2024 and 2025 — expect them again on Tuesday.

Booklet A Q1–14 and Booklet B Q29–34 are Life Science. "Explain why": give the cause, not a restatement.

Plants — Reproduction (11)

Pollination to fertilisationPollen joins the ovule on the stigma to form a seed; the ovary becomes the fruit.

DispersalWind, water, animals or explosive — the seed's own feature does it: wing-like, floats, hooks, splits.

GerminationWater, air and warmth — not soil, not light. Stored food feeds the seedling until leaves grow.

Plants — Water & Food (9)

Roots, stem, leavesRoots take in water and minerals; water-carrying tubes carry them up to the leaves.

PhotosynthesisWater + carbon dioxide, with light and chlorophyll, make glucose (stored as starch) + oxygen.

Food tubes and stomataFood-carrying tubes carry food to the growing parts; water is lost as vapour through the stomata.

Life Cycles & Classification (10)

Three-stage or four-stageMosquito and butterfly: egg, larva, pupa, adult. Cockroach, grasshopper and frog: three stages.

Group by featuresInsects: six legs, three body parts. Vertebrates have a backbone — classify by what you can see.

Why we classifyAll living things grow, reproduce, respond to changes and need food, water and air.

Cells & Microorganisms (6)

Cell partsA root cell has a cell wall but no chloroplasts (no light underground); an animal cell has neither.

MicroorganismsBacteria, fungi and yeast: useful (bread, yoghurt, decay) or harmful (spoil food, disease).

Human — Breathing & Blood (4)

Breathing and the heartAir passes down the windpipe to the lungs, where gas exchange with the blood happens; exercise raises the heart rate.

Human — Digestion (4)

The path and absorptionMouth, gullet, stomach, small intestine, large intestine; digested food is absorbed in the small intestine.

Food Chains & Populations (6)

Chains and websGreen plants are the producers — the direct energy source for animals. Arrows show energy flow.

Populations and communitiesOne kind = a population; different populations = a community. Extra fertiliser shifts the numbers.

Adaptations & Man’s Impact (5)

Two kinds of adaptationStructural: fur, blubber, camouflage. Behavioural: migration, hibernation.

Man’s impactDeforestation raises carbon dioxide; pollution and habitat loss leave animals endangered or extinct.