The following points highlight the five main components of the nucleus. The components are: 1. Nuclear envelope 2. Nuclear Sap or Nucleoplasm 3. Nucleolus 4. Chromatic Reticulum 5. Chromosomes. Nucleus: Component # 1. Nuclear Envelope: The nuclear membrane or karyotheca is the outer boundary of the nucleus. It is found in the nuclei of all the eukaryotic cells. Electron [...]
In this article we will discuss about the Physicochemical Organization of Chromosome. The major chemical components of the chromosomes are DNA, proteins (histones and non-histones) and small amount of RNA. Besides these, calcium and some other minerals are also present. Histones are basic proteins that are charged positively at neutral pH. Non-histone proteins are acidic. Histones are small proteins containing [...]
The following points highlight the three special types of chromosomes. The types are: 1. Polytene Chromsomes or Salivary Gland Chromosomes 2. Lampbrush Chromosomes 3. Prokaryotic Nucleoids. Type # 1. Polytene Chromsomes or Salivary Gland Chromosomes: The giant chromosomes were first observed in the cells of salivary glands, gut, trachea and other body parts of dipteran insects by E.G. Balbiani in [...]