1. BASIC BIOLOGY BIO 101/4 Cell division Meiosis 23 Jan 2007

7. Bivalent

24. Comparison between mitosis and meiosis Meiosis Mitosis Chiasma form and crossing over occurs during prophase I. Chiasma are never formed and crossing over never occurs. Homologous chromosomes associated to form bivalen during prophase I. Chromosomes do not associate during prophase. DNA replicates once during S phase of interphase but there are two successive nuclear division. DNA replicates once during the S phase of interphase, and nucleus divides once. Only in sexual reproduction cell, gamete cell Occurs in somatic cell in all parts of the body Dividing cells are diploid Dividing cells can be diploid or haploid

25. 4 daughter cells are formed. In male human, 4 sperm cells are formed. In female human, one ovum and 3 polar bodies are formed. 2 daughter cells are formed. Daughter cells are genetically different from parental cell. In the absence of mutation, daughter cells are genetically identical to parental cell. Daughter cells have only half the number of chromosomes found in the parent cell. Daughter cells have the same number of chromosomes as the parent cell. Chromosomes move to opposite poles during anaphase I. Chromatids move to opposite poles during anaphase. Chromosomes form two rows at the equator of the cell during metaphase I. Chromosomes form a single row at the equator of the cell during metaphase. Meiosis Mitosis

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