10 min readPathway sheetSection A MCQ (1 mark) and objective (2 marks, two parts, often a flower diagram with parts to identify); Section B short answer (3 marks) or long answer (5 marks) with a labelled flower

Sexual reproduction in flowering plants

The flower is the reproductive organ. Stamens make pollen; the pistil holds ovules. After pollination and fertilisation, ovules become seeds and the ovary becomes the fruit.

Male partStamens (androecium): the anther, which bears pollen, on a stalk called the filament

Female partPistil (gynoecium): stigma, style and ovary; the ovary holds the ovules

PollinationTransfer of pollen from the anther to the stigma, by wind, water or insects

After fertilisationOvule → seed; ovary → fruit

Parts of a flower

Part	Job
Sepals	Green and leaf-like; protect the flower bud
Petals	Bright and often scented; attract insects and butterflies
Stamen (androecium): anther on a filament	Male part. The anther bears pollen grains, which hold the male sex cells; the filament holds the anther up
Stigma (top of the pistil)	Sticky tip that receives pollen
Style (middle of the pistil)	Tube through which the pollen tube grows
Ovary (base of the pistil)	Holds the ovules, which carry the female sex cells (eggs)

Bisexual vs unisexual flowers

BisexualHas both stamens and a pistil. Most flowers are like this, such as mustard and hibiscus.

UnisexualHas only stamens (a male flower) or only a pistil (a female flower). The plant may bear separate male and female flowers. Example: papaya.

Self-pollination vs cross-pollination

Self-pollinationPollen from a flower lands on the stigma of the same flower, and then fertilises its ovule.

Cross-pollinationPollen from one flower reaches the stigma of a flower on another plant of the same species. Wind, water or insects carry it.

From pollination to seed and fruit

1
Pollination: pollen reaches the sticky stigma.
2
Each pollen grain grows a pollen tube, which pushes down through the style.
3
The pollen nucleus travels down the tube and reaches an ovule in the ovary.
4★
Fertilisation: the pollen (male) nucleus fuses with the nucleus of the egg in the ovule.
5
The fertilised ovule develops into a seed. The ovary grows and ripens into the fruit, and the petals and stamens usually wither and fall.
6
Seeds are dispersed, carried away from the parent. In the right conditions they germinate into seedlings, as gram and maize seeds do.

★ key step

Activity: find the stamen and pistil in a flower

1
Take a large flower that has begun to wilt, such as a hibiscus or a lily. Do not pluck fresh flowers: they are the plant's reproductive organs and feed bees and butterflies.
2
Gently remove the sepals and petals, and count them.
3
Find the stamens. Press an anther on dark paper or your fingertip: the yellow dust is pollen.
4
Find the pistil in the centre. Touch the stigma: it feels sticky.
5
With a teacher's help, cut the swollen ovary across with a blade. Use a hand lens to see the tiny round ovules inside.
6★
Record: name each part, and say whether the flower is bisexual (both stamens and a pistil) or unisexual (only one of them).

★ key step

How to draw a flower and the pollen tube

Draw a stalk with green sepals at the base and petals above them.
In the centre, draw the flask-shaped pistil: a swollen ovary at the base with round ovules inside, a long style, and a knob-like stigma on top.
Around the pistil, draw two or three stamens, each with a thin filament and an oval anther on top.
For fertilisation: draw a pollen grain on the stigma, a pollen tube running down the style into the ovary, and its tip entering an ovule.
Label every part with straight lines.

In real life

When you eat a mango, the juicy part is the ripened ovary, and the stone holds the seed. Honeybees moving across a mustard field carry pollen from flower to flower, which is why many farmers keep bee boxes near their crops.

Exam angle

2 marks: “How is cross-pollination different from self-pollination? Give one point, and name two agents that carry pollen.” Self-pollination: pollen reaches the stigma of the same flower. Cross-pollination: pollen is carried to the stigma of a flower on another plant of the same species. Agents: wind, water or insects (any two).

3 marks: “After pollen lands on the stigma, how does it reach the egg, and what do the fertilised ovule and the ovary become?” Pollen lands on the stigma; a pollen tube grows down the style; the pollen nucleus reaches the ovule and fuses with the egg nucleus (fertilisation); the ovule becomes a seed and the ovary ripens into a fruit.

5 marks: “Draw a labelled diagram of a flower showing its reproductive parts. Describe pollination and fertilisation in it.” Labelled sepal, petal, stamen (anther, filament), pistil (stigma, style, ovary, ovules); pollination by wind, water or insects; pollen tube through the style; fusion of nuclei in the ovule; ovule → seed, ovary → fruit.

Remember it

Stamen is the pollen-maker (male); the pistil protects the ovules (female). After fertilisation the two O's grow up: ovule → seed, ovary → fruit.