Class 12 Biology - Chapter Sexual Reproduction in Flowering Plants NCERT Solutions | What is self-incompatibility? Why does s
What is self-incompatibility? Why does self-pollination not lead to seed formation in self-incompatible species?
Self-incompatibility is a genetic mechanism in angiosperms that prevents self-pollination. It develops genetic incompatibility between individuals of the same species or between individuals of different species.
The plants which exhibit this phenomenon have the ability to prevent germination of pollen grains and thus, prevent the growth of the pollen tube on the stigma of the flower. This prevents the fusion of the gametes along with the development of the embryo. As a result, no seed formation takes place.
More Questions From Class 12 Biology - Chapter Sexual Reproduction in Flowering Plants
- Q:- With a neat diagram explain the 7-celled, 8-nucleate nature of the female gametophyte.
- 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:- What are chasmogamous flowers? Can cross-pollination occur in cleistogamous flowers? Give reasons for your answer.
- 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:- What is apomixis and what is its importance?
- Q:- Differentiate between:
(a) Hypocotyl and epicotyl
(b) Coleoptile and coleorrhiza
(c) Integument and testa
(d) Perisperm and pericarp - Q:- Why is apple called a false fruit? Which part(s) of the flower forms the fruit?
- Q:- Name the parts of an angiosperm flower in which development of male and female gametophyte take place.
- Q:- Explain the role of tapetum in the formation pollen-grain wall.
Popular Questions of Class 12 Biology
- Q:- Why is reproduction essential for organisms? Answer
- Q:-
Fill in the blanks:
(a) Humans reproduce __________. (asexually/sexually)
(b) Humans are__________. (oviparous/viviparous/ovoviviparous)
(c) Fertilization is __________ in humans. (external/internal)
(d) Male and female gametes are __________. (diploid/haploid)
(e) Zygote is __________. (diploid/haploid)
(f) The process of release of the ovum from a mature follicle is called__________.
(g) Ovulation is induced by a hormone called the __________.
(h) The fusion of male and female gametes is called _____________.
(i) Fertilisation takes place in _____________.
(j) Zygote divides to form _____________which is implanted in uterus.
(k) The structure which provides vascular connection between fetus and uterus is called ____________. - Q:- What do you think is the significance of reproductive health in a society?
- Q:- Mention the advantages of selecting pea plant for experiment by Mendel.
- Q:- Group the following as nitrogenous bases and nucleosides:
Adenine, Cytidine, Thymine, Guanosine, Uracil and Cytosine. - Q:- Explain antibiotic resistance observed in bacteria in light of Darwinian selection theory.
- Q:- What are the various public health measures, which you would suggest as safeguard against infectious diseases?
- Q:- Explain in brief the role of animal husbandry in human welfare.
- Q:- Bacteria cannot be seen with the naked eyes, but these can be seen with the help of a microscope. If you have to carry a sample from your home to your biology laboratory to demonstrate the presence of microbes under a microscope, which sample would you carry and why?
- Q:- Can you list 10 recombinant proteins which are used in medical practice? Find out where they are used as therapeutics (use the internet).
Recently Viewed Questions of Class 12 Biology
- Q:- List 10 modern-day animals and using the internet resources link it to a corresponding ancient fossil. Name both.
- Q:- What is the key difference between primary and secondary sewage treatment?
- Q:- Briefly describe the following:
(a) Transcription
(b) Polymorphism
(c) Translation
(d) Bioinformatics - Q:- Define spermiogenesis and spermiation.
- Q:- Distinguish between the following:
(a) Hibernation and Aestivation
(b) Ectotherms and Endotherms - Q:- State True/False with explanation
(a) Abortions could happen spontaneously too. (True/False)
(b) Infertility is defined as the inability to produce a viable offspring and is always due to abnormalities/defects in the female partner. (True/False)
(c) Complete lactation could help as a natural method of contraception. (True/False)
(d) Creating awareness about sex related aspects is an effective method to improve reproductive health of the people. (True/False) - Q:- Name the primary and secondary lymphoid organs.
- Q:- Differentiate between a zoospore and a zygote.
- Q:- Do you think that friends can influence one to take alcohol/drugs? If yes, how may one protect himself/herself from such an influence?
- Q:- Explain (in one or two lines) the function of the followings:
(a) Promoter
(b) tRNA
(c) Exons
6 Comment(s) on this Question
Good
Good thnks
Very easy to understand all the things
Thank you
Thanks
It is very good
- All Chapters Of Class 12 Biology
- All Subjects Of Class 12