Class 12th Biology 2017 Set1 Delhi Board Paper Solution
Arrange the following hormones in the sequence of their secretion in a pregnant woman.
Mention their source and the function they perform.
hcG ; LH ; FSH ; Relaxin (hPL)
(a) FSH, LH, hcG, (hPL)
(b)
hcG: If fertilization and implantation do occur, the corpus luetum is maintained by hcG, which takes the job of pituitary LH after fertilization.
Source: Placenta
LH: LH Act as the Leydigs cell and stimulates synthesis and secretion of androgens. Androgens stimulate the process of spermatogenesis.
In Females - FSH and LH affect the ovaries and uterus and the monthly cycle begins. Gonadotropins (LH and FSH) increase graually during the follicular phase and stimulates follicular development as well as secretion of estrogens by the following follicles.
Source: Anterior pituitary lob
FSH: It stimulate the follicles to produce estrogen and LH stimulates the corpus luetum to produce progestrone.
Source: Anterior pituitary lob
Relaxin (hPL): hcG, hPL and relaxin are produced in women only during pregnancy. In the later phase of pregnancy, a harmone called relaxin is also secreted by the ovary.
Source: Placenta
Popular Questions of Class 12th biology
- Q:- What is spermatogenesis? Briefly describe the process of spermatogenesis.
- Q:- Why is reproduction essential for organisms? Answer
- Q:- Write a short note on
(a) Adaptations of desert plants and animals
(b) Adaptations of plants to water scarcity
(c) Behavioural adaptations in animals
(d) Importance of light to plants
(e) Effect of temperature or water scarcity and the adaptations of animals. - Q:- With a neat diagram explain the 7-celled, 8-nucleate nature of the female gametophyte.
- Q:- What is DNA fingerprinting? Mention its application.
- Q:- Describe the structure of a seminiferous tubule.
- Q:- What is oogenesis? Give a brief account of oogenesis.
- Q:- What is triple fusion? Where and how does it take place? Name the nuclei involved in triple fusion.
- Q:- With a neat, labelled diagram, describe the parts of a typical angiosperm ovule.
- Q:- Explain the Law of Dominance using a monohybrid cross.
Recently Viewed Questions of Class 12th biology
- Q:- What are sacred groves? What is their role in conservation?
- Q:- What is self-incompatibility? Why does self-pollination not lead to seed formation in self-incompatible species?
- Q:- Diagrammatically represent the experimental steps in cloning and expressing an human gene (say the gene for growth hormone) into a bacterium like E. coli ?
- Q:- Differentiate between microsporogenesis and megasporogenesis. Which type of cell division occurs during these events? Name the structures formed at the end of these two events.
- Q:-
Define external fertilization. Mention its disadvantages.
- Q:- Identify each part in a flowering plant and write whether it is haploid (n) or diploid (2n).
(a) Ovary _______________
(b) Anther _______________
(c) Egg _________________
(d) Pollen__________________
(e) Male gamete _______________
(f ) Zygote ___________________ - Q:- Outline salient features of carbon cycling in an ecosystem.
- Q:- Describe one example of adaptive radiation.
- Q:- List two essential roles of ribosome during translation.
- Q:- Draw a labeled diagram of male reproductive system.