20 Questions with Answers and Explanations on “Sexual Reproduction in Flowering Plants” for Biology Students:
Q. 1. How would you define a flower being a biologist?
Ans. A flower is a reproductive structure of a flowering plant, which is a morphological and embryological marvel and a site of sexual reproduction.
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Q. 2. Define the term dithecous?
Ans. Dithecous means a structure having two layers or theca.
Q. 3. Name the tissue present in young anther.
Ans. Sporogenous tissue.
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Q. 4. Name the processes that help the release of pollen grains.
Ans. Dehydration of anther tissue and dehiscence of anther.
Q. 5. Which organic materials constitute exine and intine of a pollen grain?
Ans. (i) Exine — sporopollenin
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(ii) Intine — cellulose, pectin.
Q. 6. Name the plant responsible for pollen allergy in India.
Ans. Parthenium (carrot grass).
Q. 7. Define the terms— Syncarpous or Apocarpus.
Ans. Syncarpous :
The fused condition of pistils is called syncarpous.
Apocarpus :
The free condition of pistils is called apocarpus.
Q. 8. Which cell division forms embryo sac or female gametophyte?
Ans. Meiosis — reduction division.
Q. 9. What is the number of megaspores produced in a ovule (megasporangium)? How many are functional?
Ans. Four, one.
Q. 10. Name the parts of an angiospermic flower in which development of male and female gametophyte takes place.
Ans. Anther and ovule.
Q. 11. Arrange the following terms in the correct developmental sequence.
Pollen grain, sporagenous tissue, microspore tetrad, pollen mother cell, male gametes.
Ans. Sporagenous tissue, microspore tetrad, pollen mother cell (PMC), pollen grain, male gametes.
Q. 12. What is egg apparatus?
Ans. The three cells grouped together at the micropolar end of the embryo sac is called egg apparatus.
Q. 13. Mention the nucleus and cell status of an anigiosperm embryo sac at maturity.
Ans. 8-nucleated and 7-celled.
Q. 14. Mention one difference between chasmogamous and cleistogamous flower.
Ans. Chasmogamous: A flower with exposed anther and stigma is chasmogamous flower.
cleistogamous :A flower that does not open (i.e. anther and stigma is not exposed) is cleistogamous flower.
Q. 15. What are corn cob tussles/silk hairs like structures?
Ans. These structures are stigma and style of corn cob (that wave in wind to trap pollen grains).
Q. 16. Mention two strategies evolved to prevent self-pollination in flowers.
Ans. 1. Release of pollens is not synchronised with maturity of stigma in a flower.
2. Different positions (height) of anthers and stigma in a flower.
Q. 17. What is meant by monosporic development of female gametophyte?
Ans. The method of formation of embryo sac from a single megaspore is called monosporic development.
Q. 18. If emasculation is to be done, in which flower it can be done, unisexual or bisexual?
Ans. Bisexual flower.
Q. 19. Define scutellum.
Ans. The single cotyledon in the embryo of grass family is called scutellum.
Q. 20. Define perisperm.
Ans. The residual, persistant nucellus present in a seed is called perisperm .e.g. black pepper, beet.