RAJASTHAN PMT Rajasthan - PMT Solved Paper-2010

  • question_answer
    Which one of the following pairs of plants structures has haploid number of chromosomes?

    A)  Megaspore mother cell and antipodal cells

    B)  Egg cell and antipodal cells

    C)  Nucellus and antipodal cells

    D)  Egg nucleus and secondary nucleus

    Correct Answer: B

    Solution :

    In angiosperms, a single diploid megaspore mother cell matures within an ovule. Through meiosis, it gives rise to four megaspores (haploid). In most plants, only one of these megaspores survive. This functional megaspore divides three times by mitosis and produces eight haploid nuclei enclosed within a 7-celled embryo sac. One nucleus is located near the opening of embryo sac in egg cell. Two nuclei are located in a single cell in the middle of embryo sac and are called polar nuclei, two nuclei are contained in cells called synergids that flank the egg cell and other three nuclei are resided in the cells called antipodals, located at the end of embryo sac, opposite to the egg cell. Nucellus is centrally located mass of thin-walled parenchymatous cells covered by integuments in ovule.


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