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A male zygote develops by mitosis into a microsporophyte, which at maturity produces one or more microsporangia. Microspores develop within the microsporangium by meiosis. In a willow (like all seed plants) the zygote first develops into an embryo microsporophyte within the ovule (a megasporangium enclosed in one or more protective layers of ...
Pteridophytes consist of two separate but related classes, whose nomenclature has varied. [3] [10] The system put forward by the Pteridophyte Phylogeny Group in 2016, PPG I, is: [2] Class Lycopodiopsida Bartl. – lycophytes: clubmosses, quillworts and spikemosses; 3 extant orders; Order Lycopodiales DC. ex Bercht. & J.Presl – clubmosses; 1 ...
The Neuronal cell cycle represents the life cycle of the biological cell, its creation, reproduction and eventual death. The process by which cells divide into two daughter cells is called mitosis. Once these cells are formed they enter G1, the phase in which many of the proteins needed to replicate DNA are made. After G1, the cells enter S ...
Megagametogenesis is the process of maturation of the female gametophyte, or megagametophyte, in plants. [1] During the process of megagametogenesis, the megaspore, which arises from megasporogenesis, develops into the embryonic sac, in which the female gamete is housed. [2] These megaspores then develop into the haploid female gametophytes. [2]
The cell cycle in eukaryotes: I = Interphase, M = Mitosis, G 0 = Gap 0, G 1 = Gap 1, G 2 = Gap 2, S = Synthesis, G 3 = Gap 3. Cell division is the process by which a parent cell divides into two daughter cells. [1] Cell division usually occurs as part of a larger cell cycle in which the cell grows and replicates its chromosome(s) before dividing.
The germinating oospore undergoes mitosis and gives rise to diploid hyphae which reproduce asexually via mitotic zoospores as long as conditions are favorable. In diatoms, fertilization gives rise to a zygote termed auxospore. Besides sexual reproduction and as a resting stage, the function of an auxospore is the restoration of the original ...
The mature embryonic sac of an unfertilized ovule is 7-cellular and 8-nucleate. It is arranged in the form of 3+1+3 (from top to bottom) i.e. 3 antipodal cells, 1 central cell (binucleate), 2 synergids & 1 egg cell. One sperm fertilizes the egg cell and the other sperm fuses with the two polar nuclei of the large central cell of the ...
[3] [4] Although the centrosome has a key role in efficient mitosis in animal cells, it is not essential in certain fly and flatworm species. [5] [6] [7] Centrosomes are composed of two centrioles arranged at right angles to each other, and surrounded by a dense, highly structured [8] mass of protein termed the pericentriolar material (PCM).