In this article we will discuss about:- 1. Meaning of Chromosomes 2. Chromosome Number 3. General Morphology. Meaning of Chromosomes: In 1875, Strasburger discovered thread-like structures which appeared during cell division. Later, these structures were termed as chromosomes (chroma = colour; soma = body) by Waldeyer in 1888 since they showed affinity for basic dyes and could be stained deeply, [...]
In this article we will discuss about the replication of genetic RNA. Several viruses and bacteriophages contain single- or double-stranded RNA as their genetic material (Table 3.1). Replication of these RNA chromosomes occurs in the host cytoplasm following one of the two modes given below: (i) Direct use of RNA template for RNA synthesis (RNA RNA) by the enzyme -'RNA [...]
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 [...]