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This duplication is done during the S phase of the cell cycle. The centrosomes organise the production of microtubules that form the spindle fibres that constitute the mitotic spindle.
To do this, the mother cell must duplicate its chromosomes before cellular division. The replicated chromosomes are attached to a 'mitotic apparatus' that aligns them and then separates the sister chromatids to produce an even partitioning of the genetic material. Mitotic divisions of the zygote and daughter cells are then responsible for the subsequent growth and development of the organism. Rate this...
Chromosomes are classified on account of their size, location with respect to the centromere and presence or absence of satellites D. Her articles have appeared in magazines such as "Herb Companion" and "Northwest Travel" and she is the author of six books.
The final cellular division to form two new cells.
Besides, chromatin contains Histones chromosome proteins and other proteins involved in the packaging of the DNA strands during condensation at cell division see figure E here below and small quantities of RNA. The preparation has been made by dispersion of the chromatin in a basic solution followed by imaging in an electron microscope " Miller spread".
Gametes -- the egg or sperm cells that fuse with reproductive cells of the opposite sex -- still replicate their chromosomes during the S phase, but undergo a double split in meiosis to end up with only half the chromosome package. Because both halves receive a new half strand, the cell ends up with a double set of chromosomes.
Interphase is the G1, or gap 1, phase in which the new cell grows and carries out its functions in the body; the S, or synthesis, phase when the chromosomes replicate; and the G2, or gap 2, phase, when the cell grows further and prepares to divide.
Chromosomes and chromatids contain chromatin , which mainly consists of extremely long stands of DNA material Deoxyribonucleic acid that functions as carrier of genes and regulatory elements.
Light microscopy techniques.
The nuclear membrane reforms around the chromosomes grouped at either pole of the cell, the chromosomes uncoil and become diffuse, and the spindle fibres disappear. The homologous chromosomes pair and exchange DNA to form recombinant chromosomes.
The number of possible arrangements is 2 n , where n is the number of chromosomes in a haploid set.