# "Explain" questions — OCR GCSE Biology A: Gateway Science (J247)

> 70 questions · biology

## How to answer

WHAT + WHY. Every point paired with a because. Structure: X happens because Y. This causes Z because … Assessment Objective: AO2. Every "explain" answer on this spec is marked against exactly this pattern.

## Sample questions

1. [A yeast cell is a eukaryotic cell. Explain why a yeast cell contains mitochondria but does not contain chloroplasts.](https://www.gradenine.co.uk/q/a-yeast-cell-is-a-eukaryotic-064b0809)
2. [A cat breeder notices that some cats in a litter have short fur and some have long fur. Short fur is controlled by a dom…](https://www.gradenine.co.uk/q/a-cat-breeder-notices-that-some-097ae0ad)
3. [A population of giraffes lives in a grassland habitat where food at ground level becomes increasingly scarce. Some giraf…](https://www.gradenine.co.uk/q/a-population-of-giraffes-lives-in-0a0edfbe)
4. [A plant can produce either red flowers or white flowers. Red flower colour is controlled by a dominant allele (R). White…](https://www.gradenine.co.uk/q/a-plant-can-produce-either-red-0c6b5fdb)
5. [A bacterial cell is a prokaryotic cell. Explain why bacterial cells do not have mitochondria yet are still able to carry…](https://www.gradenine.co.uk/q/a-bacterial-cell-is-a-prokaryotic-0e44f37e)
6. [A person has not drunk any water for several hours and their blood water concentration has dropped below the normal leve…](https://www.gradenine.co.uk/q/a-person-has-not-drunk-any-121b7402)
7. [A farmer breeds guinea pigs. Some guinea pigs have smooth coat and some have rough coat. The allele for rough coat (R) i…](https://www.gradenine.co.uk/q/a-farmer-breeds-guinea-pigs-some-14c2eab2)
8. [Explain how the endocrine system responds when blood glucose concentration falls below the optimum level.](https://www.gradenine.co.uk/q/explain-how-the-endocrine-system-responds-1f77cbb2)

## Related

- [OCR GCSE Biology A: Gateway Science (J247) revision notes](https://www.gradenine.co.uk/learn/ocr-gcse-biology-a-gateway-science-j247)
- [OCR GCSE Biology A: Gateway Science (J247) past papers](https://www.gradenine.co.uk/past-papers/ocr-gcse-biology-a-gateway-science-j247)
- [Practise with AI marking (free)](https://www.gradenine.co.uk/start)