1.(Biology) a type of cell division in which a nucleus divides into four daughter nuclei, each containing half the chromosome number of the parent nucleus: occurs in all sexually reproducing organisms in which haploid gametes or spores are produced. ComparemitosisSee alsoprophase2 ...
Inducing stem cells to form primordial germ cells Stem cell therapy is a cornerstone of regenerative medicine. Based on the mechanisms underlying oocyte development into gametes, research focuses on developing methods to induce the maturation of secondary oocytes from stem cells that are capable of fer...
Related to haploid:Haploid number hap·loid (hăp′loid′) adj. Having a single set of unpaired chromosomes, as in a germ cell, such as an egg or sperm, or in a moss plant or a drone bee. n. An organism having haploid cells. ...
In flowering plants the haploid gametophytes are sexually dimorphic and produce the gametes, which fuse to produce the diploid sporophyte of the next generation. The megagametophyte of maize follows the Polygonum-type pattern of development:one of the four meiotic products, the functional megaspore,...
On the other hand, FSH has receptors on Sertoli cells of the seminiferous tubules and upstream ducts exiting the testes modulating spermatocytogenesis of the spermatogenesis i.e. taking the haploid spermatogonia to spermatocytes and producing estrogens and having receptors for it. These sex steroid ...
[126]. Primary oocytes, which are diploid cells in the initial stage of meiosis, contain a substantial amount of nutrients and mRNA. As they move forward into secondary oocytes, they become haploid cells after the first meiosis and contain fewer nutrients and mRNA [127]. Finally, mature eggs...
Sexual commitment happens before the stage of schizogony 9, 10, 11, 12, and all merozoites derived from one schizont develop into either microgametocytes (males) or macrogametocytes (females) 13, 14. The lack of sex chromosomes in haploid Plasmodium hampers our understanding of the commitment ...
(male), are formed late during development, i.e., a subepidermal layer of archesporial cells differentiates into microspore mother cells in anther primordia, while megaspore mother cells differentiate from a single subepidermal cell in the tips of ovule primordia (Grossniklaus and Schneitz1998; ...
The cells have an abundant cover of extracellular polysaccharides [8], which have been reported to protect against desiccation in rock-inhabiting fungi [18], and which might also have a protective role at high salinity. Apart from an almost four-fold increase in the size of cell clumps, the...
Since gametes (from the Greek gamos = wedding) fuse with other cells, they must themselves be haploid in nature to avoid a constant duplication of the chromosome set. This is achieved by meiosis and the formation of a haploid spore. Whereas in animal systems the gamete develops directly from...