Cytology

A domain is the highest taxonomic level of species in biology. In 1977, Woese and his coworkers developed the groundbreaking three-domain system.  They proposed this classification based on differences in the sequences of nucleotides in the cell’s ribosomal RNAs (known as 16S rRNA). They created the first worldwide tree of …

In order to grow, cells have two options. They must either replicate themselves to create more cells, or the cells themselves must expand in volume. In humans, tissues such as the skin and blood contain cells that are actively dividing, while other tissues such as fat contain cells that expand. …

If we observe the nucleus of each cell, we’ll find that the DNA molecule in it is packaged into thread-like structures. These are called chromosomes that carry hereditary information for everything, i.e., height to eye color. These chromosomes are made up of DNA that is tightly coiled many times around …

Do you have ever heard the term ‘POMATO’ ? Pomato is the result of the hybridization of two somatic cell- potato and tomato. From a somatic cell, developed by the fusion of protoplasts from potato and tomato, is cultured to get a new harvest- pomato. In this harvest, the characteristics …

Mitosis is one kind of cell division that occurs in the somatic cells of the body. It produces two daughter cells in each division. The daughter cells have the same number of chromosomes as in mother cells. Therefore, the Haploid mother cell (n) will produce two haploid daughter cells (n) …

All living things, as well as human beings, are made up of cells. Some organisms have only one cell during their whole lifespan by which they carry out all the physiological processes they require to survive. These are unicellular organisms. For instance, bacteria, yeast, etc. In contrast, there are also …

As human beings are social creatures, they live in a social environment. If we look around us, we can see mainly two types of things in the environment. One is living things & another is non-living things. Living things are those which possess life. Now, what is life? It’s not …

Chromosome behaviour is an important factor that determine the pattern of variation and taxonomic distinctness. Pairing behavior and subsequent separation of chromosome occurs at meiosis. In reporting results of pairing studies, univalents are represented by Is, bivalents by IIs, etc. Some taxonomic information can be gained from the study of …

Study of chromosome structure is very important in cytotaxonomic studies. It includes chromosome size, shape and position of centromere (i.e. arm-length ratio of each chromosome in the genome) Chromosomal size and shape are also important as taxonomic criteria in taxonomy. For examples, The chromosomal ratio if Mediola and Trillium of …

Karyotype Most living organisms have chromosomes as the structural and functional units of genetic information in their cells. The number and appearance of chromosomes vary species to species. A karyotype is an organized profile of total chromosomes in a species or in an individual organism. It gives a preliminary idea …