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Nucleic Acids/types of Nucleic Acids// DNA//RNA

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                             NUCLEIC ACIDS PART 1- DNA (DEOXYRIBONUCLEIC ACID) The nucleic acid found in microorganism (e.g. Viruses, Bacteria), plants and animals carry the genetic informations. A nucleic acid is the polynucleotide that is polymer of nucleotides. Nucleic acid are mainly found in Nucleus and therefore called Nucleic acid . Nucleic acids are responsible for the transmission of characters from parents to offspring. F. Miescher, in 1868 first time isolated nucleic acid from WBCs (White Blood Corpuscles). Nucleic acids are two types- A.    DNA (Deoxyribonucleic Acid) B.    RNA( Ribonucleic Acid) A.   DNA (Deoxyribonucleic Acid)- DNA is found in all plants, animals, prokaryotes and some viruses. In eukaryotes, DNA is present inside the Nucleu s but can also occur in   Mitochondria and Chl...
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Structure of Chromosome// Chromosomes

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  STUCTURE OF CHROMOSOMES Chromosomes were 1 st time observed by Hofmeister . The term chromosome was given by W.Waldeyer . During cell division the chromatin material gets condensed to form chromosomes. Chromosome can be best studied at metaphase stage of the cell division. Chromosome is called as Genetic carrier because it contains specific segments of genetic information and carrythis information to the next generation. Number, size, and shape of chromosome in a particular species is fixed. Minimum number of chromosome is found in Haplopappusgracilis (2n= 4) and maximum number of chromosome is found in Aulocantha (2n=1600). Chromosome consists following parts:- a.      Centromere- Centromere is located in primary constriction. b.     Chromatids- During Metaphase the chromosome consist of two symmetrical structures, which called Chromatids . Chromosomes may contain a single chromatid or may contain two chromatids. ...
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Meiosis or meiotic division//Cell division

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  Cell division part:2 Meiosis or meiotic division   Meiosis : Meiosis is also called Reductional Division or Meiotic Division. The term meiosis was given by Farmer and Moore in 1905. Meiosis occurs in special cells called Meiocytes . For example, germ cells of sex organ, Pollen mother cell etc. Meiosis is a special type of division in which number of chromosome becomes the half of the parental cell. From one diploid parental cell, four (4) haploid daughter cells are formed.   Meiosis involves two divisions- 1. Meiosis I or Reductional Division or Heterotypic Division 2. Meiosis II or   Homotypic Division   1.   Meiosis I or Reductional division or Heterotypic division - It is also called Reductional Division because it involves formation of two daughter cells each with half the number of chromosomes as compared to the parent cell. It is completed into two phases- A.    Karyokinesis I B.    Cytokines...
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