In an embryo sac, the cells that degenerate after fertilisation are:
a. Synergids and primary endosperm cell
b. Synergids and antipodals
c. Antipodals and primary endosperm cell
d. Egg and antipodals.
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Which of the following does not lose their nucleus at maturity? (a) Companion cells (b) Red blood cells (c) Vessel (d) Sieve tube cells
(a) Companion cells
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Can an unfertilised, apomictic embryo sac give rise to a diploid embryo? If yes, then how?
Yes, if the embryo develops from the cells of nucellus or integument it will be diploid.
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Why does the zygote begin to divide only after the division of primary endosperm cell?
The zygote needs nourishment during its development. As the mature, fertilised embryo sac offers very little nourishment to the zygote, the PECdivides and generates the endosperm tissue which nourishes the zygote.Hence,...
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Embryo sacs of some apomictic species appear normal but contain diploid cells
It is true that many apomicts posses normal looking embryo sacs. The only possibility of the embryo sac possessing diploid cells is due to failure of meiotic division at the...
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‘Degenerate’ and ‘Universal’ are salient features of a genetic code. Explain.
Degenerate - Some aminoacids are coded by more than one codon Universal - one codon shall code for the same amino acid in all organisms (UUU would code for phenylalanine...
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what is difference between secondary cells and primary cells?
A primary cell cannot be recharged whereas a secondary cell can be recharged. In a primary cell chemical reaction is irreversible whereas in a secondary cell chemical reaction is reversible. The internal...
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Embryo sac is to ovule as _______ is to an anther. a. Stamen
c. Pollen grain
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In a fertilised embryo sac, the haploid, diploid and triploid structures are: a. Synergid, zygote and primary endosperm nucleus
a. Synergid, zygote and primary endosperm nucleus
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In a flower, if the megaspore mother cell forms megaspores without undergoing meiosis and if one of the megaspores develops into an embryo sac,
b. The megaspores develops into an embryo sac, its nuclei would be Diploid
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In a certain language, tir me sac means green and tasty, dic sac for means tomato is green,
(A) for tir dic In the first and second statements, the common code word is green and the common word is sac. So, green means sac. In the first and third...
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