Eisenbach M , 2003 : Why are sperm cells phagocytosed by leukocytes in the female genital tract? Med Hypotheses 60 , 590 – 592 .Eisenbach M. Why are sperm cells phagocytosed by leukocytes in the female genital tract? Med Hypotheses 2003; 60: 590-592. [Medline] [CrossRef]...
In animals, gametes are formed from the undifferentiated primary germinal cells of the gonads, known as the primordial germ cells - primordial sperm cells in spermatogenesis and primordial ovum cells in oogenesis.Answer and Explanation: Primary spermatocytes are f...
While all cells within the body of a multicellular organism contain the same genetic sequence information, each lineage has undergone specialisations to become a skin cell, hair cell, heart cell and so forth. These phenotypic differences are inherited from mother cells to daughter cells. The ...
BM-derived GFP+ transgenic Oct-4+SSEA-1/3/4+ cells isolated from the BM of GFP+ chicken gave rise to functional sperm after injection into chicken 1Stem Cell Institute, James Graham Brown Cancer Center, University of Louisville, Louisville, KY, USA and 2Department of Regenerative Medicine, ...
several steps, one of which is the formation of a large protein structure called the synaptonemal complex. Like a bridge, the complex holds chromosome pairs in place enabling necessary genetic exchanges to occur that are essential for the chromosomes to then correctly separate into sperm and eggs....
In the cell, flagella are long, singular, whip-like structures that propel the cell around like in sperm. Cilia are found in multiples around a cell and beat in unison to move the cell around like in the respiratory tract where it can also move around mucus and debris....
For example, most males produce large numbers of sperm, and so multiple rounds of mitosis could result in a higher mutation rate in males than females. Alternatively, in mammals, genes on the Y chromosome could evolve rapidly simply because the lack of repair during recombination facil...
They are hermaphrodites and have the male and female reproduction organs. They exchange their sperm with other planarians to fertilize their eggs. When the eggs are fertilized, they are kept inside the planarian. In a couple months later, the eggs hatch and grow into adults. This helps the ...
This is a result of asymmetric segregation of the X chromosome in male meiosis II, which gives rise to XX sperm. As a result, either one or two paternally-derived X chromosomes are eliminated from the embryo, which initiates female (XX) or male (X0) development, respectively (Fig. 1B)...
Why do some species employ both mitosis and meiosis, whereas other species use only mitosis? A. they need only mitosis to make large numbers of cells such as sperm. B. they need meiosis if the cells are producing organs such as ovaries. C. they need both ...