These eleven questions mix all five skills in plant reproduction: flower structure, pollination and fertilisation, seeds and fruits, sexual and asexual reproduction, and germination data. They are original and ordered from easier to harder.
Write each answer on paper in full sentences before opening the answer. Any experimental data here is invented for practice. Log the questions you miss in the mistake log and retest queue.
Questions
1. Name the part of a flower that (a) makes pollen, (b) catches pollen, (c) contains ovules.
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(a) Anther. (b) Stigma. (c) Ovary.
2. State what the ovule and the ovary become after fertilisation.
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The fertilised ovule becomes the seed, and the ovary (its wall) becomes the fruit.
3. A flower has small green petals, anthers hanging outside on long filaments, and a feathery stigma. Is it insect-pollinated or wind-pollinated? Give two reasons.
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Wind-pollinated. Small green petals give no reason for insects to visit, and exposed anthers and a feathery stigma suit catching and releasing pollen in moving air. Each feature matches a job, such as a large surface area for catching pollen.
4. Write “pollination” or “fertilisation” for each: (a) pollen lands on a stigma; (b) the male nucleus fuses with the female nucleus; (c) an insect carries pollen between two flowers.
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(a) Pollination. (b) Fertilisation. (c) Pollination.
5. An ovary contains 12 ovules. Nine are fertilised. How many seeds form, and what happens to the other ovules?
Show answer
One fertilised ovule becomes one seed, so 9 seeds form. 12 − 9 = 3 ovules were not fertilised and do not become seeds.
6. Put these in order: zygote forms; pollen lands on stigma; pollen tube grows down style; male nucleus enters ovule.
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Pollen lands on stigma, then pollen tube grows down the style, then male nucleus enters the ovule, then zygote forms.
7. Explain the job of (a) the cotyledons and (b) the radicle in a seed.
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(a) The cotyledons store food that supports the seedling before it can photosynthesise. (b) The radicle becomes the root.
8. A fruit has hooks on its surface. Explain how the hooks help the plant.
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The hooks catch on the fur of passing animals, so the fruit is carried away from the parent. This reduces competition between parent and seedlings for light, water and mineral ions.
9. The data are invented. A student puts 25 seeds in each set-up and counts germination after 5 days. Results: A damp, 25 °C, light: 23; B dry, 25 °C, light: 0; C damp, 25 °C, dark: 22; D damp, 4 °C, light: 2. Give the percentage for each and state what the data show about water, light and temperature.
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A: 23/25 = 92%. B: 0/25 = 0%. C: 22/25 = 88%. D: 2/25 = 8%.
B shows water is needed. D shows a suitable temperature is needed, since almost none germinated at 4 °C. C is close to A, a gap of 1 seed, so light does not appear to be needed, though a repeat would make this stronger.
10. A farmer wants 50 plants identical to one excellent parent. Should she use seeds or cuttings? Explain and state one risk.
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Use cuttings, which are asexual reproduction, so each new plant is a genetically identical clone of the parent. The risk is that the plants all share the same weakness, so a single disease could affect the whole crop.
11. In a fictional model, a plant with genotype Aa is crossed with another Aa, where a is a recessive allele. (a) What fraction of seedlings are expected to be aa? (b) Of 8 seedlings, how many aa are expected, and why might the real count differ?
Show answer
(a) The four equally likely combinations are AA, Aa, Aa, aa, so 1/4 are aa. (b) 1/4 × 8 = 2 expected. A small number of seedlings will not match the model exactly, because each fertilisation is a chance event. The inheritance model board shows this fictional model and is not a prediction for real plants.
If you got these wrong
Match the error to the lesson that repairs it.
| If you slipped on | Revisit |
|---|---|
| Naming parts or linking a feature to its job (Q1, Q3) | Identify flower structures by role |
| Swapping pollination and fertilisation, or the sequence (Q4, Q6) | Distinguish pollination from fertilisation |
| Ovule versus ovary, seed contents, dispersal (Q2, Q5, Q7, Q8) | Explain seed and fruit formation |
| Clones versus variation, advantages and risks (Q10, Q11) | Compare sexual and asexual propagation conceptually |
| Percentages, controls, deciding what data show (Q9) | Interpret germination results with controlled conditions |
If several questions in a row went wrong, go back to the start of the module page and study the lessons in order. When you can explain each answer aloud without looking, the topic is secure.
Some students find that written explanations are where marks leak, not the recall. Our teachers work on that kind of pattern in online one-to-one Biology tuition.