In this article we will discuss about the Structure and Functions of DNA. Structure of DNA: DNA or deoxyribose nucleic acid is a helically twisted double chain polydeoxyribonucleotide macromolecule which constitutes the genetic material of all organisms with the exception of riboviruses. In prokaryotes it occurs in nucleoid and plasmids. This DNA is usually circular. In eukaryotes, most of the [...]
The following points highlight the three main constituents of nucleus. The constituents are: 1. Nuclear Envelope 2. Nucleolus 3. Nucleoplasm. Constituent # 1. Nuclear Envelope: Under the electron microscope the nuclear envelope appears to consist of two membranes, the outer and the inner nuclear membranes, separated by a perinuclear space of 20 nm (Fig. 2.65). Each of the two membranes [...]
In this article we will discuss about the Nucleus of Controlling Centre of Cell. The protoplast of eukaryotic cell contains prominent spherical or subspherical body called the nucleus (Pl.—nuclei) which controls all the life activities. As a rule, there is only one nucleus in one cell, but there are certain exceptions to this general rule. There may be many nuclei [...]