Flower parts — stamen is male, carpel is female
Sepals protect the bud; petals attract insects. The stamen is the male part: filament (supports the anther) plus anther (makes and releases pollen). The carpel is the female part: stigma (receives pollen), style (the pollen tube's route) and ovary (holds the ovules). After fertilisation the ovule becomes the seed and the ovary the fruit. Learn the two groupings — stamen = filament + anther, carpel = stigma + style + ovary — as questions ask for the parts, not the label.
Pollination transfers, fertilisation fuses
Pollination is the transfer of pollen grains from an anther to a stigma — a physical event, done by an insect or by the wind, with no nuclei involved. Fertilisation is the fusion of a pollen nucleus with a nucleus in an ovule, and it comes later: a pollen tube grows from the grain on the stigma, down the style, into the ovary and into an ovule. Order: pollen released → pollination → pollen tube grows → fertilisation → ovule becomes a seed, ovary becomes a fruit.
Germination needs exactly three conditions
Water activates the enzymes and softens the seed coat (testa). Oxygen supports aerobic respiration, which releases the energy for growth. A suitable temperature keeps those enzymes working — too cold and they are too slow, too hot and they denature. The syllabus limits germination to these three and no others: the seed lives on its own stored food until the first leaves appear, which is exactly why light and soil nutrients are absent from the list.
Drawn from real examiner reports.
Germination: not light, not nutrients
A seed germinates on its own stored food, so neither light nor soil nutrients earns a mark. The credited list is exactly water, oxygen and a suitable temperature — no more, no fewer. Bare "temperature" is also refused: the word suitable carries the biology, because germination fails both when the enzymes are too cold to work and when they are hot enough to denature.
Flagged Jun 2022 P41 Q7e; Nov 2022 P33 Q1aii; Jun 2023 P31 Q4bii
Pollination ≠ fertilisation
These are two events, not two words for one thing. Pollination is a transfer: pollen moves from an anther to a stigma and nothing fuses. Fertilisation is a fusion: a pollen nucleus joins a nucleus in an ovule, after a pollen tube has grown down the style. Check every answer against its verb — does it describe a transfer, or a fusion of nuclei?
Flagged Nov 2023 P12 Q10
Anther produces, stigma receives
The anther sits on the male stamen and produces and releases pollen; the stigma tops the female carpel and receives it. Giving the reverse — the stigma making pollen, or the anther catching it — is a recurring examiner complaint. Fix it by pairing each structure with one verb: anther produces, stigma receives, ovary contains the ovules, ovule becomes the seed.
Flagged Nov 2022 P32 Q10a
A carpel is three parts, not one
Answering "the carpel" or "the female part" has not named anything. A carpel is the stigma (receives pollen), the style (connects stigma to ovary and carries the pollen tube) and the ovary (holds the ovules). A stamen splits the same way into filament and anther. A question asking for the parts wants those names, not the group label.
Flagged Nov 2022 P32 Q10a
Pollinated but not fertilised
Judge each event against its own definition. If pollen reaches a stigma but the pollen tube never delivers a nucleus to an ovule, pollination HAS occurred and fertilisation has not — so no seed forms in that ovule. The reverse is impossible: fertilisation can never happen unless pollination came first.
Wind flowers: name the anther and stigma
"Small dull petals, no scent" is the easy half of the answer and is often all that is offered. The features being asked for are the anthers — large, loosely attached, hanging outside the flower on long filaments — and the stigma — large, feathery or branched, also hanging outside. Both are Extended (Supplement) content, 0654 B15.3.7.
Feature, job, benefit
For any adaptation question use one chain: name the structure ("large feathery stigma"), say what it does ("large surface area out in moving air"), then say why that helps ("more likely to trap pollen carried past on the wind"). A feature listed on its own drops the linking mark.
Match the command word
"Identify" = name it from the diagram, nothing more. "State the function" = the one-line role ("the anther produces pollen"). "Describe the structural adaptations" = each feature plus the job it does. "Explain why" = the full chain through to the benefit.
Give all three germination conditions
Unless the question restricts you to one, write water, oxygen and a suitable temperature every time — a partial list is not fully credited, and the word "suitable" must travel with "temperature".
Ovule to seed, ovary to fruit
"Develops into" questions have one correct pairing: after fertilisation the ovule becomes the seed and the ovary becomes the fruit. Reversing them, or writing that the ovary becomes the seed, throws away a mark that needs no reasoning at all.
Cambridge 0654 spec reference: Section B15 "Reproduction", sub-topic B15.3 (Core content 1-6; Extended/Supplement content 7). This leaf covers the parts of an insect-pollinated flower and their functions, the definitions of pollination and fertilisation, the structural adaptations of insect- vs wind-pollinated flowers, the environmental conditions needed for seed germination, and (Extended) the specific anther and stigma features of a wind-pollinated flower.
Out of scope for B15.3 (do not use): self-/cross-pollination terminology, fruit/seed dispersal mechanisms, seed internal structure beyond what a germination investigation needs, double fertilisation or pollen-tube growth mechanisms.
| Term | Mark-scheme-precise definition / function |
|---|---|
| Sepal | Protects the flower bud before it opens |
| Petal | Attracts pollinating insects (large and brightly coloured in insect-pollinated flowers) |
| Stamen | The male part of the flower = filament + anther |
| Filament | The stalk that supports the anther |
| Anther | Produces and releases pollen grains (contain the male gamete nucleus) |
| Carpel | The female part of the flower = stigma + style + ovary |
| Stigma | Receives pollen grains during pollination |
| Style | Connects the stigma to the ovary; the pollen tube grows through it |
| Ovary | Contains the ovules; develops into the fruit after fertilisation |
| Ovule | Contains the female gamete nucleus; develops into the seed after fertilisation |
| Pollination | The transfer of pollen grains from an anther to a stigma |
| Fertilisation (plant) | Occurs when a pollen nucleus fuses with a nucleus in an ovule |
| Germination | The conditions needed are limited to: water, oxygen and a suitable temperature |
The one idea that unlocks the topic: pollination is a transfer (physical movement of pollen); fertilisation is a fusion (chemical joining of nuclei) — they are two separate, sequential events.
Define pollination and fertilisation in a flowering plant.
A student investigated the effect of oxygen availability on seed germination (illustrative data). Two identical sets of seeds were placed on damp cotton wool at the same suitable temperature.
After 6 days, 27 out of 30 seeds in Set A had germinated, and 3 out of 30 seeds in Set B had germinated.
(a) Calculate the percentage germination for Set A. (2 marks)
(b) Explain why the percentage germination for Set B was so much lower than for Set A. (2 marks)
