Chromosome : Chromosomes are long thread like structure which contain the basic unit of inheritance which is known as genes.
Histone protein: Histone protein neutralizes the acidity of DNA , prevents it from mutation and wraps around it.
Function of histone protein :
1.DNA molecule can be stored in a smaller space and in condensed form
2.Unexpressed gene can be wrapped more tightly for heterochromatin to suppress the gene expression of unwanted genes.
In Eukaryotic cells, a chromosome is made up of one long molecule of DNA and histone protein and are situated within the nucleus. In Prokaryotic cells, a chromosome is made up only DNA molecule and no histone protein and is situated within the nucleus. Chromosomes can be found in two forms: 1.Chromatin 2.Chromatids Chromatin: Chromatin is the dispersed form of chromosome.Chromatin consists of : 1.Euchromatin : Lossely coiled party of the gene containing active genes 2.Heterochromatin: Tightly coiled part containing gene in inactive form. Chromatids: Before nuclear division, DNA replication occurs, so each chromosome is doubled up. Each chromosome can be seen containing identical sister chromatids attached by centromere.
Nuclear Division
Nuclear divisions are of two types: mitosis and meosis.
Mitosis:
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