In this article we will discuss about some cytological slides and specimen. 1. B-Chromosome or Supernumerary Chromosome: i. The nuclei of some animals or plants contain one or more chromosomes in addition to normal chromosomes. These additional chromosomes are called B-chromosomes or supernumerary chromosomes. ii. First described by Wilson in 1905 in Metapodius, an insect, these chromosomes have now been [...]
The following points highlight the six main cell organelles of protoplasm. The cell organelles are: 1. Chloroplast 2. Mitochondria 3. Golgi Apparatus 4. Nucleus 5. Endoplasmic Reticulum 6. DNA Model. Cell Organelle # 1. Chloroplast: 1. Chloroplasts (Figs. 18, 19), responsible for the photosynthesis of the plants, are the characteristic features of the cells of green plants. 2. Around the [...]
In this article we will discuss about Viruses:- 1. Meaning of Viruses 2. Sizes and Shapes of Viruses 3. Structure. Meaning of Viruses: Virus is a Latin word which means poison. Adolf Mayer described for the first time a disease of tobacco plant. Dimitri Ivanowski, a Russian botanist in 1892 demonstrated experimentally that sap of mosaic tobacco plant was capable [...]