Monthly Archives: March 2019

Chromosomal Aberration: Structural and Numerical

What is Chromosomal Aberration? Any type of change in the structure and number of chromosomes due to certain irregularities during cell division is known as chromosomal aberration. Broadly such aberrations are divided into two major groups. Structural aberration Numerical aberration Again, structural aberrations are of 4 types. Such as: Deletion …

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Solenoid Model: The Second Level of Packing

In the nucleosome model of chromosome, we have discussed about the fundamental organizational unit of chromosome termed as nucleosome. That article gave us a simplistic idea about how the repeated nucleosomes are arranged. The figure in the right hand side clarifies that the nucleosome model provides us with the insight …

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Nucleosome Model of Chromosomes

Let’s kick off this discussion with a simple calculation about the length of DNA in a single diploid human cell. We know according to Watson and Crick model of double helix DNA, each two base pairs has a distance of 3.4 A. There are approximately 6.4 billion base pairs (bp) …

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The Megasporangium: Types, Parts and Functions

Megasporangium is the structure of a plant body which contains female reproductive organ . It can be called ovule .  It consists of nucellus and integument . The ovule can be formed in different size and shape . Many times it changes its form during the course of its development. …

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Coliform Bacteria: An Indicator of Water Contamination

Coliform commonly known as ” indicator organisms” , refers to a wide groups of bacteria ( about 16 species) that  found throughout the environment and used to evaluate the water quality.  These organisms have a wide distribution in soil, water surface, vegetations as well as on the skin or intestinal …

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The Microsporangium & the Male Gametophyte

Microsporangium: The sporangium that is connected with the production of microspores (pollen grains) eventually development of male gametophyte is known as microsporangium. Microsporangia are produced on stamen where each stamen has a bilobed anther (each lobe has two microsporangia), connective and anther filament. When anther produces four elongated microsporangia, the …

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