10 questions · Form 4 Biology Bab 14: Sexual Reproduction, Development and Growth in Humans and Animals
What main event occurs during the stationary phase of a classic sigmoid growth curve?
Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.
1. What main event occurs during the stationary phase of a classic sigmoid growth curve?
Answer: A
In the stationary phase, overall growth reaches equilibrium as cell division rate balances cell mortality.
2. At what stage of cell division is the secondary oocyte held prior to successful fertilization by a sperm?
Answer: C
During oogenesis, the secondary oocyte starts Meiosis II but pauses at Metaphase II until fertilization triggers completion.
3. Which hormone is mainly responsible for repairing and rebuilding the endometrial lining of the uterus following menstruation?
Answer: B
Estrogen secreted by developing ovarian follicles promotes vascular growth and tissue repair of the endometrium during the proliferative phase.
4. What is the primary role of the fluid inside the amniotic sac surrounding the developing foetus?
Answer: B
Amniotic fluid protects the foetus from mechanical injury, allows free physical movement, and helps maintain body temperature.
5. During the menstrual cycle, what structural entity secretes high amounts of progesterone after ovulation occurs?
Answer: B
After releasing the oocyte, the ruptured Graafian follicle transforms into the yellow corpus luteum, which secretes progesterone.
6. Why are human testes housed outside the main abdominal cavity inside the scrotum?
Answer: B
Sperm production requires a temperature 2°C to 3°C lower than core body temperature, which is maintained by the external position of the scrotum.
7. Which hormone surge directly triggers ovulation (release of the secondary oocyte) around Day 14 of the menstrual cycle?
Answer: B
A sharp rise in Luteinizing Hormone (LH surge) triggers the rupture of the Graafian follicle and release of the secondary oocyte.
8. How many functional mature ova are produced from a single primary oocyte at the completion of oogenesis?
Answer: C
Oogenesis produces only 1 functional, nutrient-rich ovum along with 3 tiny polar bodies that degenerate.
9. Why does maternal blood and fetal blood remain separated inside the placenta?
Answer: B
Separation of blood streams prevents damage to delicate fetal microvessels and avoids fatal immune reactions if blood types differ.
10. Which structure connects the embryo to the placenta and houses blood vessels for exchange?
Answer: B
The umbilical cord links the fetal abdomen to the placenta, carrying umbilical arteries and veins.