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  Practical Notebook Biology Standard XII Biology  Answeres Practical Notebook Standard XII Class-12th science Click here download in PDF 9. Demonstration of hybridization technique  Introduction Hybridization is one of the methods of crop improvement undertaken to combine the and female parents.   The technique involves the following steps:  desired, useful characteristics from two different pure varieties of plant species, selected as male & Collection of pollen grains  (Anthesis): Pollen grains from the flower of the selected male parent are collected in sterile paper bags and are stored in clean and dry vials at a cool place.  The collection is done in the early hours of the morning.  Day, date, and time of Anthesis are recorded.  b.   Emasculation:  It is the removal of young anthers of the stamens in the plant selected as the female parent having bisexual flowers, well before anthesis i.e. formation of pollen grains.  The bisexual flower of a female parent is emasculated. Bu

  Practical Notebook Biology Standard XII Biology  Answeres Practical Notebook Standard XII Class-12th science Click here download in PDF https://drive.google.com/file/d/10NrtEg6k0Hh8ttkenvZvI2EzFqZN8vPr/view?usp=sharing 7. Study of meiosis in onion flower bud with the help of permanent slides.  Aim:  To study and identify different stages of meiosis.  Principle 1 Meiosis is a special type of cell division that occurs in the diploid reproductive or germ tissue (cells).  It is a reduction division that results in the formation of four haploid daughter cells each receiving half of the total number of chromosomes than those present in the mother cell from which it is produced Observation For the preparation of meiosis slides, generally, anther of Lily or Onion is used.  Meiosis can be studied with the help of stained permanent slides of T. S. of the anther.  Permanent slides should be observed under the high power of a compound microscope.  Meiosis is a process that occurs in two steps vi

  Practical Notebook Biology Standard XII Biology  Answeres Practical Notebook Standard XII Class-12th science Click here download in PDF 9. Isolation of DNA from Given Sample  Aim:  To extract and isolate DNA from a fruit sample.   Requirements: -  Fleshy berry fruits like banana, Zizyphus, grapes, etc, can be used.  Fleshy fruits of banana, liquid soap, distilled water, salt (NaCl), 1000 ml ice-cold isopropyl alcohol i.e.  IPA (Chill the alcohol (IPA) by placing the test tube in a beaker containing ice cubes and some water] measuring spoons, glass stirring rod, test tubes, glass beakers, plastic cups, strainer or coffee filter, funnel, etc. Principle:  All plants' DNA extraction protocols comprise the basic steps of disruption of a cell wall, cell membrane, and nuclear membrane to release the DNA into solution followed by precipitation of DNA and ensuring removal of the contaminating biomolecules.  A figure is separated by physical means such as grinding,  to form a mash  The ce