List the main differences between mitosis and meiosis.
MitosisMeiosis
1. The cell divides only once after one round of DNA replication. 1. There are two successive cell divisions; the first and the second meiotic divisions.
2. Mitosis takes place in the somatic cells. 2. Meiosis takes place in the germ cells.
3. It occurs in both sexually as well as asexually reproducing organisms. 3. It occurs only in sexually reproducing organisms.
4. The DNA replicates once for one cell division. 4. The DNA replicates once for two cell divisions.
5. The duration of prophase is short; usually for a few hours. 5. Prophase is comparatively longer and may take days.
6. Prophase is comparatively simple. 6. Prophase is complicated and is divided into leptotene, zygotene, pachytene, diplotene and diakinesis.
7. There is no synapsis.   7. Synapsis of homologous chromosomes takes place during prophase I.
8. The two chromatids of a chromosome do not exchange segments during prophase. 8. The chromatids of two homologous chromosomes exchange homologous segments during the pachytene stage of prophase.
9. During prophase and metaphase, each chromosome consists of two chromatids held together by a centromere. 9. During prophase and metaphase, homologous chromosomes form bivalents. Each bivalent has four chromatids and two centromeres.
10. The arms of the chromatids are close to one another during prophase. 10. The arms of the chromatids are separated widely during prophase II.
11. Division of centromeres takes place during anaphase. 11. There is no centromeric division during anaphase I. Centromeres divide only during anaphase II.
12. Spindle fibres disappear completely in telophase. 12. Spindle fibres do not disappear completely during telophase I.
13. Nucleoli reappear at telophase. 13. Nucleoli do not reappear at telophase I.
14. The chromosome number remains constant at the end of mitosis. 14. The chromosomal number is reduced from diploid to haploid.
15. The genetic constitution of daughter cells is identical to that of the parent cell. 15. The genetic constitution of the daughter cells usually differs from that of the parent cell due to crossing over. Each chromosome of daughter cells usually contains a mixture of maternal and paternal genes.
 
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