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 [...]
Learn about the Comparison between Meiosis and Mitosis. Comparison # Meiosis: 1. In mitosis, chromosome doubling is followed by separation of daughter chromosomes, i.e., there is division of centromere in mitosis. 2. Mitosis occurs in all the cells of the body. 3. It completes in one sequence of stages, i.e., there is only series of divisional stages. Prophase: 4. Prophase [...]
The below mentioned article provides an overview on Ribonucleic Acid (RNA). In broad features, the chemistry of RNA is comparable to the chemistry of DNA. The chemical analysis shows the following two main differences in the polynucleotide chains of DNA and RNA: (i) The sugar in RNA is ribose whereas it is deoxyribose in DNA. (ii) While in DNA, the [...]