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Ask QuestionPosted by Bommi Suresh 6 years, 4 months ago
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Posted by Janvi Dahre 6 years, 4 months ago
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Gaurav Seth 6 years, 4 months ago
As the anther develops, the cells of the sporogenous tissue undergo meiotic divisions to form microspore tetrads. As each cell of the sporogenous tissue is capable of giving rise to a microspore tetrad. Each one is a potential pollen or microspore mother cell (PMC). The process of formation of microspores from a pollen mother cell through meiosis is called microsporogenesis. The microspores, as
they are formed, are arranged in a cluster of four cells–the microspore
tetrad. As the anthers mature and dehydrate, the microspores dissociate from each other and develop into pollen grains. Inside each microsporangium several thousands of microspores or pollen grains are formed that are released with the dehiscence of anther.
Posted by Janvi Dahre 6 years, 4 months ago
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Posted by Janvi Dahre 6 years, 4 months ago
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Gaurav Seth 6 years, 4 months ago
The process of fusion of the sperm and the ovum is known as fertilization. During fertilization the sperm induces changes in the zona pellucida and blocks the entry of other sperms. This ensures that only one sperm fertilizers an ovum.The enzymatic secretions of the acrosome help the sperm enter the cytoplasm of the ovum. This causes the completion of meiotic division of the secondary oocyte, resulting in the formation of a haploid ovum and a secondary polar body. Then, the haploid sperm nucleus fuses with the haploid nuclues of the ovum to form a diploid zygote.
Posted by Giriraj Gaurav 6 years, 4 months ago
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Meghna Thapar 5 years, 8 months ago
Smaller animals tend to have larger surface area to volume ratios. For instance, a hamster has a larger surface area relative to its volume than an elephant! Elephants have adapted to losing heat faster by having very large ears. This increases their surface area to volume ratio. Small Animals have a larger surface area relative to their volume they tend to loose body heat very fast when it is cold outside and they have to expend much energy to generate body heat through metabolism.
Posted by Anita Kumari 6 years, 4 months ago
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Yogita Ingle 6 years, 4 months ago
In graphical forms, steeper slopes means slopes which are closer to vertical axis, or in other words they make larger angle with horizontal axis.
In case of species area relationship given by Alexander von Humboldt, steeper slopes (Z values in the range of 0.6 to 1.2) are obtained when species relationships are plotted among very large areas like the entire continents. Steeper slopes signifies that number of species found increases faster than the area explored in very large areas like the entire continents.
Posted by Pj Aj 6 years, 4 months ago
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Vijeta Bhadana 6 years, 4 months ago
Posted by Tanu Sharma 6 years, 4 months ago
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Yogita Ingle 6 years, 4 months ago
VNTR is a small fragment of DNA containing tandemlyy repeated sequence, whose number and length vary among chromosome and individuals. VNTR shows a high level of polymorphism and is specific for different individual, whereas Probe is a small fragment of DNA or RNA used for identification of genes in biological system. These fragments are prepared for commercial and hybridization technology either for finding complementary sequence or in the diagnosis of some diseases.
Posted by Dhamendra Yadav 6 years, 4 months ago
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Vijeta Bhadana 6 years, 4 months ago
Posted by Rajnish Shridhar 6 years, 4 months ago
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Posted by Palak Khandelwal 6 years, 4 months ago
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Yogita Ingle 6 years, 4 months ago
The flow of the glomerular filtrate in the two limbs of Henle’s loop and the vasa recta is in a counter-current pattern.
NaCl is transported by the ascending limb of Henle’s loop which is exchanged with the descending limb of the vasa recta.
NaCl is returned to the interstitium by the descending portion of the vasa recta.
Similarly, minute quantities of urea enter the thin segment of Henle’s loop which is transported back to the interstitium by the collecting tubule.
The counter-current pattern and the proximity between the Henle’s loop and the vasa recta help to maintain the osmolarity in the inner medullary interstitium, i.e. 300 mOsmoiL−1 in the cortex and 1200 mOsmoiL−1 in the medulla.
This process is called the counter-current mechanism.
Posted by Palak Khandelwal 6 years, 4 months ago
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Melody Hanjabam 6 years, 4 months ago
Posted by Vicky Kumar 6 years, 4 months ago
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Yogita Ingle 6 years, 4 months ago
The use of biology to develop technologies and products for the welfare of human beings is known as Biotechnology. It has various applications in different fields such as Therapeutics, Diagnostics, Processed Food, Waste Management, Energy Production, Genetically Modified Crops etc.
Posted by Rajwant Gill 6 years, 4 months ago
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Sheeja Menon 6 years, 4 months ago
Posted by Mar Dsk 6 years, 4 months ago
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Noorine Qureshi 6 years, 4 months ago
Posted by Kunal Singh 6 years, 4 months ago
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Posted by Sonal Meena 6 years, 4 months ago
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Yogita Ingle 6 years, 4 months ago
Nature's biological library is burning even before we catalogued the titles of all books stocked there. The statement is fully justified. There are myriad species that are yet to be discovered and named which requires a lot of manpower to go in it. Considering the number of species that are at the verge of getting instinct it seems we will never be able to reach the number which the species hold that are not even discovered.
Posted by Melody Hanjabam 6 years, 4 months ago
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Posted by Vimal Maurya 6 years, 4 months ago
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Sia ? 6 years, 4 months ago
Emasculation is important in crop improvement programmes and it is done to obtain superior varieties of plants. It is done to prevent self pollination in the plant and then desired pollen grains are used for pollination to obtain hybrid variety of plants..</div>
Posted by Vinayak S Sangannanavar 6 years, 4 months ago
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Sri Venk 6 years, 4 months ago
Posted by Ahmad Kashan Zain 6 years, 4 months ago
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Son Sammy 6 years, 4 months ago
Gagan Singh 6 years, 4 months ago
Posted by Suraj Pandey 6 years, 4 months ago
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Posted by Prakash Tailors 6 years, 4 months ago
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Meghna Thapar 5 years, 8 months ago
Meselson and Stahl Experiment was an experimental proof for semiconservative DNA replication. In 1958, Matthew Meselson and Franklin Stahl conducted an experiment on E. coli which divides in 20 minutes, to study the replication of DNA. The experiment done by Meselson and Stahl demonstrated that DNA replicated semi-conservatively, meaning that each strand in a DNA molecule serves as a template for synthesis of a new, complementary strand. Meselson and Stahl tested the hypothesis of DNA replication. They cultured bacteria in a 15N medium. 15N is a heavy isotope of nitrogen so the DNA synthesized is of heavy density. They then shifted the bacteria to a 14N medium, DNA was isolated at different times corresponding to replication cycles 0, 1, and 2. The Meselson-Stahl experiment enabled researchers to explain how DNA replicates, thereby providing a physical basis for the genetic phenomena of heredity and diseases. The Meselson-Stahl experiment stemmed from a debate in the 1950s among scientists about how DNA replicated, or copied, itself.
Posted by Deep Nagra 6 years, 4 months ago
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Vishal Soni 6 years, 4 months ago
Alok Kumar 6 years, 4 months ago
Posted by Deep Nagra 6 years, 4 months ago
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Posted by Rakhi Rock 6 years, 4 months ago
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Ayan Ansari 6 years, 4 months ago
Saheb Ok 6 years, 4 months ago
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