Download App

Human Reproduction — BIOLOGY STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceBIOLOGYHuman Reproduction5 Marks
Question
When does oogenesis start in humans? Name the three hormones and their source, linked with oogenesis. How do they influence the process of oogenesis? Explain.
✓

Answer

Oogenesis starts during the embryonic developmental stages in the female foetus.

The hormones involved are:

  1. Follicle stimulating hormone (FSH)
  2. Luteinising hormone (LH).
  3. Progesterone.
  1. Follicle stimulating hormone (FSH):
  • FSH stimulates the growth and development of ovarian follicles into a mature Graafian follicle.
  • It also stimulates the secretion of estrogen from the follicle cells.
  1. Luteinising hormone (LH):
  • LH stimulates the rupture of mature follicle and ovulation.
  • It also stimulates the formation of corpus luteum from the ruptured follicle and secretion of progesterone from it.
  1. Progesterone:
  • Progesterone is necessary to maintain the endometrium and implantation.
  • In the absence of fertilisation, the corpus luteum degenerates and consequently the endometrium also degenerates leading to menstruation.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "5 Marks Questions" from Human Reproduction→Human Reproduction — all question types→BIOLOGY STD 12 Science question papers→Gujarat Board STD 12 Science question papers→Gujarat Board question paper generator→

Similar questions

(i) What is called immunity?
(ii) Write the difference between active immunity and passive immunity. (Sr. Sec. Board Exam., 2023)
(iii) Explain passive immunization. (iv) Make a labeled diagram of the stages of life cycle of Plasmodium in mosquito host.
→
A youth in his twenties met with an accident and succumbed to the injuries. His parents agreed to donate his organs. So, their:
  1. List any two essential clinical steps to be undertaken before any organ transplant.
  2. Why is the transplant rejected sometimes?
  3. What views would you share with your health club members to promote organ donation?
→
Provide genetic explanation for the observation in which the flower colour in F1 generation of snapdragon did not resemble either of the two parents. However, the parental characters reappeared when F1 progenies were selfed.
→
Mention three applications and future challenges of human genome project.
→
Malarial parasite ‘Plasmodium’ completes its life cycle in two hosts. Draw its complete life cycle and explain various stages it follows throughout its life.
→
How is the phenotypic ratio of F2 generation different in a dihybrid cross?
→
Explain insertional inactivation.
→
  1. Draw a labelled diagram of L.S. of an embryo of grass (any six labels).
  2. Give reason for each of the following:
  1. Anthers of angiosperm flowers are described as dithecous.
  2. Hybrid seeds have to be produced year after year.
→
One chromosome contains one molecule of DNA. In eukaryotes the length of the DNA molecule is enormously large. Explain how such a long molecule fits into the tiny chromosomes seen at metaphase.
→
Avinash went to his village during his summer vacations. One day, he decided to visit the nearby forest and asked his grandfather to accompany him. His grandfather told him about the recent cutting of forest and the new factory which had been established. Hearing this Avinash became curious and explained his grandfather about the ecosystem services.
  1. What are the benefits of healthy forest ecosystem?
  2. Explain the contribution of Robert Constanza in ecosystem services.
  3. What factors account for cost of various ecosystem services?
  4. What values are shown by Avinash?
→