Sexual Reproduction in Flowering Plants Class 12 Biology Important Questions
Please refer to Sexual Reproduction in Flowering Plants Class 12 Biology Important Questions with answers below. These solved questions for Chapter 2 Sexual Reproduction in Flowering Plants in NCERT Book for Class 12 Biology have been prepared based on the latest syllabus and examination guidelines issued by CBSE, NCERT, and KVS. Students should learn these solved problems properly as these will help them to get better marks in your class tests and examinations. You will also be able to understand how to write answers properly. Revise these questions and answers regularly. We have provided Notes for Class 12 Biology for all chapters in your textbooks.
Important Questions Class 12 Biology Chapter 2 Sexual Reproduction in Flowering Plants
All Sexual Reproduction in Flowering Plants Class 12 Biology Important Questions provided below have been prepared by expert teachers of Standard 12 Biology. Please learn them and let us know if you have any questions.
Question. What is the ploidy of the cells in the microspore tetrad?
Answer : Haploid
Question. Explain the structure of pollen grain.
Answer : Exine- sporopollenin resistant organic material,intine –cellulose and pectin, generative cell ,vegetative cell
Question. How many eggs are present in an embryo sac?
Answer : One
Question. Explain the structure of microsporangium.
Answer : Wall layers , epidermis , endothecium , middle layers – protection , tapetumnourishes , sporogenous tissue.
Question. What is scutellum?
Answer : Cotyledon of monocot
Question. What is pollination and explain its types?
Answer : Transfer of pollen grains auto gamy- same flower ,geitonogamydifferent flower, xenogamy- different plant of same plant
Question. What is a pollen bank?
Answer : Stored pollen
Question. Identify the given figure and label the parts.
Answer : a. Pollen sac b. pollen grains c. line of dehiscence d. filament.
Question. Why are pollen grains produced in enormous quantity in maize?
Answer : Compensate to the losses during transfer of pollens
Question. Of the eight nuclei of the embryo sac in flowering plants three are at the micropylar end. How many are there at the chalazal end and how many nuclei located in the central cell?
Answer : Three – chalazal end, two – central cell
Question. What are the characteristics of wind ,water and insect pollinated flowers?
Answer : Wind-large amount of pollens ,light non-sticky ,well exposed stamens, feathery stigma Water – mucilaginous covering, long ribbon –like Insect-large, colourful, fragrant , nectar
Question. What are the effects of pollen in some people and how are the pollen grains are being used as food supplements?
Answer : Cause severe allergies and bronchial afflictions ,tablet and syrups
Question. Continued self-pollination result in inbreeding depression. What are the out breeding devices developed in flowering plants to discourage self-pollination? Which type of pollination seen in Papaya?
Answer : Non –synchronisation of stigma receptivity and pollen release, different positions, self-incompatibility, unisexual flowers /xenogamy
Question. Why is the process of fertilization in flowering plant referred to as double fertilization? Explain.
Answer : Syngamy and triple fusion take place in an embryo sac
Question. Define triple fusion. What is the product of this process? What does the product develop into?
Answer : Male gamete moves towards two polar nuclei located in central cell and fuses to produce triploid primary endosperm nucleus involves fusion of three nuclei – triple fusion , PEN – product , Endosperm
Question. How does geitonogamy differ from xenogamy in plants?
Answer : Transfer of pollen grains from anther to stigma of another flower of same plant, different palnt /genetically similar, different
Question. What are the stages of embryogeny in a Dicotyledonous embryo?
Answer : Proembryo , globular , heart-shaped , mature embryo
Question. How long do the seeds remain alive after they are dispersed?
Answer : In a few species lose viability within a few months ,live for several years in some species.
Question. Explain artificial hybridization technique.
Answer : Emasculation- removal of anther, bagging- to prevent contamination, dusting of desired pollen on stigma, rebagging
Question. Explain double fertilization schematically.
Answer : Male gamete + egg——->Zygote—->Embryo(Syngamy).
Male gamete + two polar nuclei–>triple fusion —>PEN…endosperm
Question. What is the ploidy of PEN?
Answer : Triploid
Question. Endosperm development precedes embryo development. Why?
Answer : PEC divides to form endosperm tissue – filled with reserve food material, nutrition of the developing embryo
Question. Explain the following terms : Non-albuminous, Albuminous, Perisperm, Pericarp, seed dormancy.
Answer : No residual endosperm, retain endosperm, residual persistent nucellus, fruit wall, state of inactivity
Question. Explain free nuclear endosperm development.
Answer : PEN –>successive nuclear divisions , cell wall formation occurs later –endosperm
Question. What are advantages of seeds to Angiosperms?
Answer : Pollination and fertilization are independent of water-seed formation is more dependable ,better strategies for dispersal to new habitats ,hard seed coat provides protection to embryo
Question. How many haploid nuclei and haploid cells are present in the female gametophyte of angiosperm?
Answer : 8-nucleate 7-celled
Question. What do you mean by seed dormancy? What is its significance?
Answer : Water content is reduced seeds become dry, metabolic activity slows down, state of inactivity, storage of seeds –food throughout the year / raise crop in next season
Question. Explain the pollen pistil interaction with a sketch showing entry of pollen tube into asynergid.
Answer : Dialogue by chemical components pollen grain ,germinates to produce pollen tube ,content move into pollen tube, grows through stigma ,style reaches ovary , generative cell divide into two male gametes enters through micropyle, filiform apparatus guides the entry
Question. Trace the development of a mature female gametophyte from a megaspore mother cell.
Answer : MMC – meiosis, four megaspores, three degenerate, one functional develop into embryo sac, mitosis of nucleus 2- nucleate, one mitosis 4-nucleate one mitosis 8 nucleate egg apparatus, polar nuclei in central cell, antipodals.
Question. Even though each pollen grain has two male gametes, why are at least 10 pollen grains and not 5 pollen grains required to fertilize 10 ovules present in a particular carpel?
Answer : Double fertilisation
Question. What are parthenocarpic fruits?
Answer : Fruits formed without fertilisation
Question. Describe the development of male gametophyte in angiosperms.
Answer : MMC- meiosis – microspore tetrad, pollen grains exine, sporopollenin, intine, germ pore, vegetative cell, generative cell, two male gametes
Question. Explain the following terms : False fruit ,True fruit, Parthenocarpic fruit, Apomixis, Polyembryony.
Answer : Thalamus become fruit, ovary becomes fruit , fruit formation without fertilisation, produce seeds without fertilization ,more than one embrgo in a seed.
Question. How could pollen grains be well preserved as fossils?
Answer : Sporopollenin , highly resistant organic material forms exine
Question. Mr.Y, a farmer has kept heaps of seeds to be packed for future use in a room. His children while playing poured water on to the seeds.
A) As a student of biology suggest the measures to be taken before storage and why?
B) What is the significance of seeds for a farmer?
Answer : (A) Measures to be taken before storage with reason
(B) Significance of seeds for farmers