Observation of Mitosis

Observation of Mitosis intromission Reproduction is the biological process by which new individual organisms be produced. There atomic number 18 devil types of reproduction, which are a informal and sexual reproduction. agamous reproduction is creation of offspring whose genes all come from superstar parent. Sexual reproduction is creation of offspring by fusion of male gametes (sperm) and female gametes (eggs) to form zygotes. Asexual reproduction involves a type of cubicle division known as mitosis. Mitosis is the scientific term for thermonuclear cell division, where thenucleusof the cell divides, resulting in two sets of samechromosomes.Mitosis is accompanied bycytokinesisin which the hold back result is two completely separate cells called girl cells. There are quadruple phases of mitosis prophase,metaphase, anaphase and telophase. The active sites of cell division in plants are known as meristems and they are convenient source of mitotic cells for observation benea th the glint microscope. In this experiment two different methods had been used. One of the methods that bemuse been used was Feulgen Reaction, origin tips have been fixed and stained using this reaction.This histochemical method is specific for DNA which is stained deep red-purple. Aim canvass the stages of mitosis under light microscope. Method 1 Preparation of Root Squash and Observation of Mitosis in garlic Root Meristems Firstly, one and only(a) root tip was taken from a container by using a pipette. This root tip was putted on a slide and a drop of 80% glycerol was added, than a coverslip applied. afterwards coverslip was applied, slide was covered with a sheet of blotting paper and squashed gently.Lastly this sample was observed under light microscope twain with low power and high power objective. Method 2 Observation of Mitosis in genus Allium SP. Root Meristems Slides of Allium sp. Root tip squashes was prepared and provided. These ready slides were observed under l ight microscope some(prenominal) low and high power objectives and stages of mitosis were drawn. Disscusion miosis has many similarities to mitosis. However, there are major differences that it is essential to note. The flurry below shows the comparison of the stages of mitosis and meiosis. Stages Meiosis MitosisInterphase begins with a diploid cell begins with a diploid cell Prophase quaternion chromosomes combine to form two tetrads the chromosomes in the tetrad cross over each other, allowing them to exchange inheri add-in material -four chromatids combine to form two chromosomes linked by a centromere Metaphase the two tetrads origination up in the plaza the two chromosomes line up in the centre Anaphase the two tetrads disunited up into four chromosomes which go to both poles the two chromosomes split up into four chromatids which move to both of the poles Telophase the two sets of chromosomes become enclosed by the nuclear windbag the two sets of chromatids are enclosed by the nuclear envelope Cytokinesis two cells are formed with two sets of chromosomes in each one dickens cells are created with two chromatids in each one. Mitosis is now complete. Prophase II DNA replication is skipped and the two cells nuclear envelope are dissolved and the stiletto heel reformed the four chromatids in each cell are connected together to form two chromosomes Metaphase II the two chromosomes line up in the centre Anaphase II the two chromosomes are split up into their daughter chromatids and moved towards opposites poles Telophase II The nuclear envelope is reformed around the two poles on each cell. Cytokenesis the cells are split up again and four haploid cells remain as a result meiosis is now complete The second table below shows the general difference between mitosis and meiosis. Mitosis Meiosis Produces body cells(Somatic cells) cells for growth and repair Produces sex cells(Gametes) cells for sexual reproduction One nuclear di vision, separating chromatids Two nuclear divisions, first separating homologic chromosomes and second separating chromatids Two daughter cells produced Four daughter cells produced Chromosome number remains same Chromosome number halved No association between homologous chromosomes Homologous chromosomes associate and form bivalents No crossing over ccurs Crossing over many extend at chiasmata Chromosomes only form single row at equator at metaphase At metaphase 1, chromosomes form ingeminate row at equator young lady cells contractableally identical with each other and parent cell little girl cells differ genetically from each other and parent cell Daughter cells have two sets of chromosomes(pairs) Daughter cells have only one member of each pair of chromosomes In metaphase chromosomes line up individually In metaphase I chromosomes line up as homologous pairs (synapsis). The two double chromosomes are called a tetrad when they are lined Comparison of the biological signific ance of mitosis and meiosis * The Significance of MitosisThe significance of mitosis is its cleverness to produce daughter cells which are exactly the same as the parent cell. It is important for three reasons 1. product If a tissue wants to get bigger by growth needs new cells that are identical to the existing ones. Cells division must therefore be by mitosis. 2. Repair Damaged cells have to be replaced by exact copies of the organism so that it repairs the tissues to their former condition. Mitosis is the means by which this is achieved. 3. Asexual reproduction If a species is good at colonizing a habitat, there might be no point, in producing offspring which are different from the parents, because they might be less effective at survival.Therefore it might bebetter, in the dead term,to make a colony which is similar to the parents. In simple animals and most plants this is achieved by mitotic division. * Significance of Meiosis The long term survival of a species depends on i ts ability to adapt to a changing environment. To do this the offspring need to be different from their parents and each other. These are three ways in which alteration occurs because of meiosis. 1. Production and fusion of haploid gametes The variety of offspring is increased by mixing the genotype of one parent with that of the other. It involves the production of special sex cells, called gametes, which fuse together to produce a new organism.Each gamete contains one-half the number of chromosomes of the adult. It is important that meiosis, which halves the number of chromosomes in daughter cells, happens at some stage in the animateness cycle of a sexually reproducing organism. Therefore Meiosis is important in order for variety in organisms, and allowing them to evolve. 2. The creation of genetic variety by the random distribution of chromosomes during metaphase 1. When the pairs of homologous chromosomes arrange themselves on the equator of the spindle during metaphase 1 of meiosis, they do it randomly. Even though each one of the pair determines the same general features, theyre detail of the feature is different.The randomness of this distribution and independent assortment of these chromosomes produces new genetic combinations. 3. The creation of genetic variety by crossing over between homologous chromosomes. During prophase 1 of meiosis, equal portions of homologous chromosomes whitethorn be swapped. In this way new genetic combinations are made and linked genes separated. The variety which meiosis brings vital for to the process of evolution. By providing a varied stock of individuals it allows the natural selection of those best suit to the existing conditions and makes sure that species constantly change and adapt when these conditions change. This is the main biological significance of meiosis. Gizem KARAGOZLU 19026857.