MEIOSIS meiosis is a process of reduction division in which the number of chromosomes per cell is cut in half and homologous chromosomes in a diploid cell are separated involves two distinct stages: meiosis I and meiosis II one diploid cell becomes 4 haploid cells homologous two sets of chromosomes (one from mom and one from dad) – if a cell has both sets of chromosomes = diploid (2n) 2 complete sets of chromosomes with 2 complete sets of genes gametes with only one set of chromosomes = haploid (n) contain only one set of genes meiosis I prior to meiosis I, each chromosome is replicated – chromosomes line-up similar to mitosis, except the homologous chromosomes for a tetrad (4 chromatids) occurs during prophase I crossing over may occur results in the exchange of alleles between homologous chromosomes – and produces new combinations of alleles homologous chromosomes separate and two new cells are formed meiosis II cells from meiosis I enter meiosis II – cell does not undergo chromosome replication anaphase II chromatids separate – Main Concept #2: Compare the processes of mitotic and meiotic nuclear division.
MEIOSIS meiosis is a process of reduction division in which the number of chromosomes per cell is cut in half and homologous chromosomes in a diploid cell are separated involves two distinct stages: meiosis I and meiosis II one diploid cell becomes 4 haploid cells homologous – two sets of chromosomes (one from mom and one from dad) if a cell has both sets of chromosomes = diploid (2n) 2 complete sets of chromosomes with 2 complete sets of genes gametes with only one set of chromosomes = haploid (n) contain only one set of genes meiosis I – prior to meiosis I, each chromosome is replicated chromosomes line-up similar to mitosis, except the homologous chromosomes for a tetrad (4 chromatids) occurs during prophase I crossing over may occur – results in the exchange of alleles between homologous chromosomes and produces new combinations of alleles homologous chromosomes separate and two new cells are formed meiosis II – cells from meiosis I enter meiosis II cell does not undergo chromosome replication anaphase II – chromatids separate Main Concept #2: Compare the processes of mitotic and meiotic nuclear division.