Question of 77
Q.The schematic representation of spermatogenesis is given here under. On the basis of the diagram, answer the following questions: (2+3=5)
(i) What will be the fate of the egg if it is not fertilized by the sperm.
(2)
(ii) Explain the different phases of oogenesis.
(3)
OR
(i) Draw a well labeled diagram of seminiferous tubules.
(2)
(ii) What is the function of sertoli cells in spermatogenesis.
(2)
(iii) Name the hormone which activates the Leydig cells to produce androgens? (1)
Himachal HpboseHPBOSE Plus Two Board 2026Subjective· 5mImportance★★★★★
0% · 0/77 Questions
You're viewing a preview — the full solution, concept, methods & PYQ mapping are locked.
Start your 14-day free trial to unlock the full solution →Note: the paper's printed heading says 'spermatogenesis', but the diagram and both sub-questions clearly describe oogenesis (egg fate, phases of oogenesis) — answered here as oogenesis, matching the diagram and sub-parts, which is honestly the intended question.
- Fate of the egg if not fertilized: The secondary oocyte released at ovulation is arrested at metaphase of meiosis II; it only completes meiosis II (producing the mature ovum and a second polar body) if a sperm fertilizes it. If fertilization does NOT occur within about 24 hours of ovulation, the unfertilized secondary oocyte degenerates. Around the same time, since no embryo implants, the corpus luteum (formed from the ruptured follicle) also degenerates, causing progesterone (and estrogen) levels to fall. This drop causes the thickened endometrial lining of the uterus to break down and shed, along with the degenerated egg, as menstrual bleeding — restarting the next menstrual cycle.
- Phases of oogenesis: Oogenesis (formation of the mature female gamete) occurs in three phases:
- Multiplication phase: During early foetal development, the primordial germ cells (oogonia) in the ovary undergo repeated mitotic divisions to increase their number.
- Growth phase: Oogonia grow in size and enter meiosis I, but the division is arrested at the diplotene stage of prophase I; these arrested cells are now called primary oocytes, each surrounded by a layer of granulosa cells to form a primary follicle. This arrest persists from before birth until puberty (and beyond, for oocytes not yet ovulated). …
Unlock everything free for 14 days
- Full step-by-step solutions
- Concept-first explanations
- Methods, shortcuts & mistakes
- PYQ mapping + timed mock tests
Full access for 14 days. No credit card required.