Tag: division for growth and reproduction
Questions Related to division for growth and reproduction
If the diploid number of an angiospermic plant is 24, the number of chromosomes in the pollen grain, endosperm and integument will be
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12, 36, 12
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12, 24, 36
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12, 12, 36
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12, 36, 24
12, 36, 24; because pollen grains are haploid while endosperm has triploid chromosome number and integument is diploid in nature.
After penetrating stigmatic and styler tissues, the pollen tube usually grow down towards the egg because
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The egg cell attracts the pollen tube as they have dissimilar electric charge
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The filiform apparatus of synergids is believed to attract the pollen tube
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It has no other passage to follow
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It grows under control of nucleus
In porogamy, filiform apparatus of synergids secretes, some chemotropically active sunstances, which direct the pollen tube towards micropyle of ovule.
Intine of pollen grain is made of.
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Callose
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Pecto-cellulose
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Cellulose
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Fat-like sporopollenin
In amoeboid type of tapetum.
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The cells remain in situ
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The cells secrete chemicals for degeneration of middle layers
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The cells pass in between the middle layers
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The cells form plasmodium that passes in between pollen grain mother cells
This type of tapetum can be seen easily in Alisma, Butomus, Tradescantia, and Typha, etc. The tapetal cells fuse among themselves for forming a tapetal plasmodium. The protoplast of the fused tapetal cells then moves into the locule, where they surround the pollen mother cells or pollen grains. This protoplast movement into the locule is taking place during meiotic prophase.
Thus the correct answer is option D.
Wall of a mature pollen grain consists of.
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Ektexine and endexine
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Tapetum and endothecium
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Exine and intine
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Foot and baculate layer
The pollen wall actually is the multi-layered structure that includes an intine, which is composed mainly of polysaccharide, and an exine, which consists mainly of sporopollenin. The exine can be further divided into the sexine and nexine. Sexine is the single layer of bacula which is covered by a layer of the tectum.
So the correct answer is C.
The function of anther is?
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Produce Ubisch bodies
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Produce pollen grains
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Store and protect pollen grains
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All the above
In ovule, archesporial cell differentiates from nucellus.
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At chalazal region
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Middle of nucellus
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Laterally near endothelium
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Hypodermally in the micropylar region
Study of formation, growth and development of new individual from an egg is?
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Apomixis
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Embryology
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Embryogeny
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Cytology
Abundant occurrence of fossilised pollen grains is due to resistant.
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Lignocellulose
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Sporopollenin
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Pectocellulose
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Pectolignin
Abundant occurrence and preservation of the fossil pollen grains result from the extremely resistant nature of the outer wall of the pollen grains. This wall is the exine and composed of a compound commonly known as sporopollenin. It originates from the polymerization of carotenoids and carotenoid esters.
Thus the correct answer is B.
Which of the following pair has haploid structures?
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Nucellus and antipodal cells
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Antipodal cells and egg cell
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Antipodal cells and megaspore mother cell
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Nucellus and primary endosperm nucleus