These seven original questions follow the four lessons in the chapter. Write your answer first, then open the model answer.
Questions
Question 1. State where spermatogenesis and oogenesis take place.
Answer
Spermatogenesis takes place in the testes, and oogenesis takes place in the ovaries.
Question 2. State two differences between a sperm and an ovum.
Answer
- A sperm is small, but an ovum is large.
- A sperm has a tail and can swim, but an ovum cannot move by itself and contains stored food.
Question 3. Explain why gametes must be made by meiosis and not by mitosis.
Answer
Meiosis halves the chromosome number, so each gamete is haploid. At fertilisation, two haploid gametes fuse, which restores the diploid number in the zygote. Mitosis would keep the diploid number, and the chromosome number would double each generation.
Question 4. State the difference between fertilisation and implantation.
Answer
Fertilisation is the fusion of the sperm nucleus and the ovum nucleus to form a zygote, in the oviduct. Implantation is the attachment of the embryo to the lining of the uterus.
Question 5. In a model cycle, LH is 5 units on day 12 and 45 units on day 14. State the change and the event it triggers.
Answer
LH rises from 5 to 45 units between day 12 and day 14. This surge triggers ovulation, the release of the ovum from the ovary.
Question 6. Progesterone is 30 units on day 21 and 3 units on day 28. Explain what happens to the uterus lining and why.
Answer
The lining breaks down by day 28. Progesterone falls from 30 to 3 units, and without it the lining cannot stay thick, so it is lost if no embryo has implanted.
Question 7. A plant is 4 cm tall at week 0, 6 cm at week 2, 16 cm at week 4, 34 cm at week 6 and 36 cm at week 8. During which period is growth fastest, and what is the rate?
Answer
Growth per period is 2, 10, 18 and 2 cm. The fastest period is weeks 4 to 6, with 34 − 16 = 18 cm gained. The rate is 18 ÷ 2 = 9 cm per week.
If you got these wrong
Questions 1 to 3 point to comparing gametogenesis within syllabus scope. Question 4 uses explaining fertilisation and early development.
Questions 5 and 6 need interpreting hormonal-cycle graphs educationally. Question 7 comes from reading growth curves and identifying phases.
Log each slip in the mistake log and paper-error review, then build a timed set with the timed original practice session builder. For a teacher to go through your answers, see online one-to-one Biology tuition.