NOTES BLOG NEPAL

Nitrogen fixation  is the process of converting free nitrogen  gas of atmosphere into nitrogen compounds (nitrites and nitrates) There are  three types of nitrogen fixation  :- Atmospheric Nitrogen fixation (by lightning) Industrial Nitrogen fixation (by chemical fertilizers) Biological Nitrogen fixation (by bacteria and blue green algae) The root nodules of legimonous plants (soybean, pea, bean) contain symbiotic nitrogen  fixing bacteria (Rhibozium) which converts atmospheric nitrogen into water soluble nitrates and fixes in the soil. It increases the fertility of soil with the increase in productivity. So,  farmers are suggested to cultivate leguminous plant on certain interval of years. The bacteria, that convert ammonia into nitrates are called as  nitrifying bacteria . Example :- Nirosomanous (Nitrite bacteria) and Nitrobacter (Nitrate bacteria). Dinitrification  is the process of conversion of nitrate salts present in the soil ...

Physics 1. (a) The body weighs more at pole than equator. Why? The mass of the planet is 6 x 10 24 kg and its radius is 6400 km. What is the weight of 50kg mass standing on that planet? (G = 6.67x10 –11 Nm 2 /kg 2 )                                                                                     [1+2+1=4]  (b) Nuclear Energy is also considered an alternative source of energy. Why? Show the complete thermonuclear reaction taking place on the surface of sun and write its two conditions. [1+2.5=3.5] 2. (a) Define Pascal’s law. If weight of a body in air is 20...

 Virus is a very tiny, infections and highly pathogenic organisms, which can multiply only within the living host. They don't have cellular structure. They contain hereditary material in the form of DNA or RNA enclosed in a protein coat called capsid. A mature virus is called a viron. They exhibit properties of both living and non-living things, as Virus has no metabolic activity of its own. They are smallest living organism with the size of about 20nm to 300 nm. Based on the host they attack, viruses are of 3 types. ·     Animal Virus ·     Plant Virus ·          Bacteriophages They are also classified into RNA virus and DNA virus on the basis of nucleic acid present in them. Q. Why is a virus considered as the boarder line between living and non living things? Virus is a living thing only inside a cell and nonliving thing outside a cell so it is considered as a chain between living and non li...

Cell division Cell division is a process of multiplication of cell by its division. It is of two major types. They are mitosis and meiosis. Mitosis Mitosis cell division is that in which one cell divides into two diploid daughter cells. It is also called educational cell division and mitotic cell division. It causes growth. Meiosis Meiosis cell division is that in which one cell divides into four haploid daughter cell. It is also called reductional cell division and meiotic cell division. It forms gamete. Mitosis Cell Division Cytokinesis Cytokinesis is division of cytoplasm and karyokinesis is division of nucleus. Karyokinesis Karyokinesis of mitosis completes in the following four main phases: Prophase Metaphase Anaphase Telophase Prophase In prophase, nucleolus disappears, nuclear membrane is disappearing, centrosome fibres is started between the centrosomes. At the last of this phase, chromosomes make their duplicates. Metaphase In metaphase,...