In his article we will discuss about the role of nucleolus in production of ribosomes (explained with diagram). The nucleolus is the site for rRNA transcription and processing as well as for assembly of ribosomal subunits. The nucleolus is organised at the nucleolus organising regions (NORs) of some chromosomes. These chromosomal regions contain the genes for 5.8S, 18S and 28S [...]
In this article we will discuss about the heterochromatin and euchromatin in eukaryotic chromosomes. The terms "heterochromatin" and "euchromatin" were given by Heitz in 1928-29, although they had been discovered much earlier. Heterochromatic blocks observed during interphase were earlier termed as pro-chromosomes. The substance of which eukaryotic chromosomes are composed is known as chromatin; it contains DNA, protein and a [...]
The following points highlight the two main ways of representing chromosome set of species. The ways are: 1. Karyogram 2. Idiogram or Idiotype. Representing Chromosome: Way # 1. Karyogram: Photomicrographs of the chromosomes of a single representative somatic metaphase cell are clipped out and arranged in homologous pairs according to their size. If the chromosomes are small and there is [...]