Biology XI Content
Differences between Mitosis and Meiosis
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S.N.
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Meiosis
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1.
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It occurs in somatic cells and in germ cells during the multiplicative phase or gametogensis.
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It occurs in reproductive cells of gonads.
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2.
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Mitosis completes in one sequence of stages i.e. in this cell division the cell divides once.
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The whole process completes into two successive divisions i.e. cell divides twice.
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3.
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In mitosis, chromosome doubling is followed by separation of daughter chromosome i.e. there is division of centromere in mitosis.
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In meiosis, there is doubling of chromosomes once which is followed by two nuclear divisions, i.e. the centromere of chromosomes divides only once usually at the meiosis-II, or equational division phase.
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4.
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The daughter cells formed by this division are genetically similar to mother cell. Amount of DNA is same as in mother cell.
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The daughter cells formed by this division are genetically different from mother cell. Amount of DNA is half to that of mother cell.
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Prophase
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Prophase
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5.
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Prophase of mitosis is of short duration and is without sub stages.
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The prophase I of meiosis is of longer duration and completes in the five sub stages, viz., Leptotene, zygotene, pachytene, diplotene and diakinesis.
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6.
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The homologous chromosomes do not pair up with each other i.e. synapsis is absent.
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In meiosis I, the homologous chromosomes form pairs during the zygotene stage and it appears as if the chromosome number has become reduced to half.
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7.
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Duplication or splitting of chromosomes takes place in the early prophase.
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Duplication or splitting of chromosomes takes place in the late prophase (Pachytene stage).
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8.
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No chiasma formation or crossing over takes place.
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chiasma formation or crossing over takes place.
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9.
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The exchange of the genetic material between the homologous chromosomes does not occur.
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The exchange of the genetic material between the homologous chromosomes occurs.
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Metaphase
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Metaphase
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10.
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Chromosomes appear double stranded i.e. the chromatids occur in the form of dyads.
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Since, homologous chromosomes do not separate in prophase I, the chromosomes pairs appear in tetrad state, i.e. four stranded in metaphase-I.
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11.
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The centromere of each chromosome divides into two and thus the two chromatids of the chromosome become free from each other.
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Centromere of the homologous chromosomes do not divide, thus their chromatids do not become free in the metaphase-I.
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Anaphase
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Anaphase
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12.
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The two chromatids of each chromosome move towards the opposite poles of spindle.
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In meiosis I, the two homologous chromosomes of each pair separate and move towards the opposite poles of spindle during anaphase stage.
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13.
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The daughter chromosomes appear in singlet state.
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The separated chromosomes are two stranded but their centromere remains still in undivided state. However, the centromere is splitted into two in the metaphase II.
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14.
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The chromosomes are long and thin.
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The chromosomes are short and thick.
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Telophase
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Telophase
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15.
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The telophase always occurs.
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The first telophase is sometimes absent.
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16.
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Number of chromosome remains same as in mother cell.
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Chromosome number becomes half than the mother cell.
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Cytokinesis
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Cytokinesis
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17.
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Cytokinesis always occurs.
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Cytokinesis-I may be absent.
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Significance
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Significance
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18.
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A diploid mother cell always produces two diploid cells by mitosis.
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A diploid cell produces four haploid cells by meiosis.
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19.
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Variations are not produced, so no role in evolution.
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Variations are produced due to crossing over, so plays important role in speciation and evolution.
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