Biology Blogs For Class 11th, 12th & NEET

                                        Megasprogenesis  The formation of megaspore mother cells from megaspore mother cells is called megasporogenesis.  This process occurs inside the nucellus of developing ovule of angiosperms. It is surrounded by a layer known as the epidermis . Below the epidermis, there is a layer known as hypodermis. One cell of hypodermic divide and grow in a bigger size which is known as archesporial cells.                                        These archesporial cells divide periclinal to form an outer parietal layer and inner sporogenous cells. These sporogenous cells function as megaspore mother cells (MMC). These cells divide meiotically and form four haploid tetrad cells. Out of which three degenerate and only one remain is functional. On...

                                          X-Ray and DSA   Introduction - It is one of the oldest methods of imaging which starts with the accidental discovery of X-ray by Wilhelm Knored Roentgen , a German physicist in 1895.  The branch of science that deals with the study of X-ray for the detection and treatment of diseases are called Radiology. Principle - High dose X-ray is passed through the body where the body absorbs this radiation and scatter this radiation to all over the body and the remaining x-ray pattern is recorded for later evolution. Uses -  X-ray imaging is usually applied in detecting bone fractures and dislocations.            This technique is also advantageous in detecting the disease of  the heart and lungs .            In Dental Examination.     ...

                                       Phylum - Chordata               Class Amphibia  As the name indicates (Gr., Amphi : dual, bios, life), amphibians can live in aquatic as well as terrestrial habitats. Most of them have two pairs of limbs. Body is divisible into head and trunk. Tail may be present in some. The amphibian skin is moist (without scales). The eyes have eyelids.  A tympanum represents the ear. Alimentary canal, urinary and reproductive tracts open into a common chamber called cloaca hich opens to the exterior. Respiration is by gills, lungs and through skin. The heart is threechambered (two auricles and one ventricle). These are cold-blooded animals. Sexes are separate. Fertilisation is external. They are oviparous and development is indirect. Earliest amphibians - Ichthyostega basically a fish wi...