中文（繁體）
中文（简体）
English
S4 Biology Cell Division, Paper 2: cell cycle and gamete numbers
S4 Biology Cell Division, Paper 2: cell cycle and gamete numbers
Paper 2 works from cells with 2n of 10 and 12 through chromosome numbers, division timing and total gamete counts.
Focus Mitosis keeps 2n and meiosis halves it, while sperm counts are four times the number of mother cells.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 |
| Suggested time | 25 |
| Difficulty mix | Foundation 4 · Intermediate 3 · Challenge 2 · Error redo 1 |
| Chapter | Chapter: S4 Biology: Cell Division |
| Level | S4 |
02 Questions (10 items)
- FoundationA cell with 2n = 10 completes mitosis. How many chromosomes per daughter cell?
- FoundationA cell with 2n = 10 completes meiosis. How many chromosomes per daughter cell?
- FoundationIn which stage of mitosis do chromosomes line up at the equator?
- FoundationHow many sperm does one primary spermatocyte finally produce?
- IntermediateA cell divides every 20 minutes. How many cells come from one after an hour?
- IntermediateA cell with 2n = 12 undergoes meiosis. What is n in the daughter cells?
- IntermediateOne cell with 2n = 24 divides by mitosis three times. How many cells and how many chromosomes each?
- ChallengeIf 100 primary spermatocytes all finish meiosis, how many sperm result?
- ChallengeA cell cycle lasts 24 hours and mitosis takes 2 hours. What percentage of the cycle is mitosis?
- Error redoError: a student says mitosis halves the chromosome number. What is correct?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | 10 | Chromosomes are copied and shared equally, so the number stays at 10. |
| 2 | 5 | Meiosis has two divisions and halves the number, so 10 becomes 5. |
| 3 | Metaphase | In metaphase the chromosomes line up at the equator, the best time to count them. |
| 4 | Four | Two divisions turn one mother cell into four haploid cells. |
| 5 | Eight | One hour holds three divisions, and 2 to the power 3 is 8. |
| 6 | 6 | Meiosis halves the chromosome number, so 12 divided by 2 gives 6. |
| 7 | Eight cells with 24 each | The count doubles each time so 2 to the power 3 is 8, and the chromosome number never changes. |
| 8 | 400 | Each mother cell yields four sperm, so 100 times 4 gives 400. |
| 9 | About 8.33 per cent | Two divided by 24 times 100 gives about 8.33, so the rest is interphase. |
| 10 | The number stays the same; meiosis halves it | Mitosis keeps 2n unchanged, and only meiosis halves the number. |
04 What to do after marking
- After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
- Repeat the same item two days later; move to the next paper only when both attempts are correct.
- Parents only need the answer and note columns; there is no need to explain every item.
Book an S4 Biology tutorTutor Registration →
Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.
