BIOL 1090 Chapter Notes - Chapter p.89-94, 98-100, 104-105: Y Chromosome, Polyploid, Heinrich Wilhelm Gottfried Von Waldeyer-Hartz
17 Oct 2016
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Chromosomes are characteristic of the nuclei of al cells. The diffuse network of threads is called chromatin, some regions of the chromatin stain more darkly than others, suggesting an underlying difference in organization. The light regions are called euchromatin and the dark regions are called heterochromatin. Within a species, the number is almost always an even multiple of a basic number; in humans the basic number is 23 mature eggs and sperm have this number of chromosomes. Most other types of human cells have twice as many (46), although a few kinds have four times (92) the basic number. The haploid, or basic chromosome number (n) defines a set of chromosomes called the haploid genome. Most somatic cells contain two of each of the chromosomes in this set and are therefore diploid (2n) Cells with four of each chromosome are tetraploid (4n), those with eight of each are octoploid (8n)
