MITOSIS AND MEIOSIS

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  • Created by: Hanna Mc
  • Created on: 30-05-16 14:17

MITOSOIS

MITOSIS IS WHEN A CELL REPRODUCES ITSELF BY SPLITTING TO FORM TWO IDENTICAL OFFSPRING. 

WHEN THE CELL GETS THE SIGNAL TO DIVIDE IT NEEDS TO DUPLICATE ITS DNA SO THERES ONE COPY FOR EACH NEW CELL. THE DNA IS COPIED AND FORMS X-SHAPED CHROMOSOMES. EACH ARM OF THE CHROMOSOME IS AN EXACT DUPLICATE OF THE OTHER. THE CHROMOSOMES THEN LINE UP AT THE CENTRE OF THE CELL AND THE CELL FIBRES PULL THEM APART. THE TWO ARMS OF EACH CHROMOSOME GO TO THE OPPOSITE ENDS OF THE CELL. MEMBRANES THEN FORM AROUND EACH OF THE SETS OF CHROMOSOMES AND THESE BECOME THE NUCLEI OF THE TWO NEW CELLS, LASTLY THE CYTOPLAST DIVIDES. 

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MITOSIS USES

ASEXUAL REPRODUCTION USES MITOSIS. 

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MEIOSIS

MEIOSIS INVOLVES TWO DIVISIONS. AS WITH MITOSIS THE CELL STARTS TO DIVIDE, DUPLICATING ITS DNA INTO EXACT COPIES. IN THE FIRST DIVISION IN MEIOSIS THE CHOMOSOME PAIRS LINE UP AND ARE PULLAD APART SO SOME OF THE MOTHERS AND FATHERS CHROMOSOMES GO INTO EACH NEW CELL. THEN IN THE SECOND DIVISION THE CHROMOSOMES ONCE AGAIN LINE UP AND THEN ARE PULLED APART TO GET 4 GEMETES WITH A SINGLE SET OF CHROMOSOMES IN IT. 

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MEIOSIS USES

DURING SEXUAL REPRODUCTION 2 GAMETES FROM A NEW INDIVIDUAL. GAMETES ONLY HAVE 1 COPY OF EACH CHROMOSOME SO YOU CAN COMBINE THEM WITH THE OPPOSITE SEX TO GET THE RIGHT NUMBER OF CHROMOSOMES. GAMETES ARE MADE BY MEIOSIS THEN AFTER THE EGG IS FERTILISED DIVIDE USING MITOSIS. 

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