BIOLOGY WITH HAMZA · MDCAT REVISION
Reproduction
Name: ____________________ Date: ______________
Recall first. Check second. Return to the ideas you missed.
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Learning targets
- Compare spermatogenesis and oogenesis.
- Explain FSH, LH, oestrogen and progesterone across the ovarian cycle.
- Trace fertilisation, implantation and early hormonal support.
Core notes
- Gamete production differs in timing, cytokinesis and number of functional products.
- FSH supports follicles; the LH surge triggers ovulation.
- Progesterone maintains the post-ovulation endometrium.
- hCG preserves the corpus luteum during early pregnancy.
Read, cover and redraw
Follicles grow and release oestrogen.
Endometrium proliferates.
High oestrogen triggers ovulation.
Progesterone supports the endometrium.
Without pregnancy, menstruation begins.
Written recall
1. Why can high oestrogen trigger an LH surge even though ovarian hormones often inhibit pituitary activity?
2. What is the immediate hormonal consequence if no implantation occurs?
Apply the idea
1. An organism has 2n = 16 chromosomes. How many chromosomes are normally present in a gamete and in a zygote after fertilisation?
- 8 and 16
- 16 and 32
- 8 and 8
- 4 and 16
My answer: _____ Reason: ____________________________________
2. Which location normally hosts fertilisation in humans?
- Uterine cavity
- Uterine tube, usually its ampulla
- Cervix
- Vagina
My answer: _____ Reason: ____________________________________
3. Which event is most closely associated with the sharp mid-cycle rise shown?
| Cycle day | Relative LH |
|---|---|
| 8 | 5 |
| 12 | 7 |
| 14 | 45 |
| 18 | 6 |
- Sperm maturation
- Menstruation on that same day in every cycle
- Ovulation
- Implantation before fertilisation
My answer: _____ Reason: ____________________________________
Answer key
Cover this section while attempting the questions.
Written recall
1. Near mid-cycle, sustained high oestrogen changes to positive feedback, strongly stimulating the pathway that produces the LH surge.
2. The corpus luteum degenerates, progesterone and oestrogen fall, and the supported endometrial state breaks down.
Applied questions
1. A — Meiosis halves the chromosome number to n = 8 in each gamete. Fusion of two haploid gametes restores 2n = 16.
2. B — Fertilisation normally occurs in the uterine tube, usually the ampulla. The developing embryo subsequently travels to the uterus, where implantation normally occurs.
3. C — A mid-cycle LH surge triggers the events leading to ovulation. The values are illustrative; timing and hormone levels vary among individuals.