BIO101 ‒ Topic 3: Cell Division (Mitosis and Meiosis)
1. Meaning and Importance of Cell Division
Cell division is the process through which a parent cell divides to form two or more
daughter cells. It is essential for growth, repair, and reproduction. In unicellular organisms,
it leads to new individuals, while in multicellular organisms, it enables tissue repair and
growth.
2. The Cell Cycle and Its Phases
The cell cycle consists of two main stages: Interphase and the Division Phase. Interphase
includes G1 (growth), S (DNA synthesis), and G2 (preparation for division). The division
phase includes Mitosis or Meiosis, followed by Cytokinesis.
3. Mitosis ‒ Stages and Significance
Mitosis results in two genetically identical daughter cells. It occurs in somatic (body) cells
and maintains chromosome number. The stages include: • Prophase ‒ Chromosomes
condense and become visible; spindle fibers form. • Metaphase ‒ Chromosomes align
along the cell s equator. • Anaphase ‒ Sister chromatids separate and move to opposite
poles. • Telophase ‒ Nuclear membranes reform, and chromosomes uncoil. • Cytokinesis ‒
Division of the cytoplasm to form two new cells. Text Diagram Description: Imagine two
identical sets of chromosomes separating equally into two new nuclei, ensuring identical
genetic material in each daughter cell.
4. Meiosis ‒ Stages and Significance
Meiosis occurs in reproductive cells (gametes) and reduces the chromosome number by
half, producing four non-identical daughter cells. It has two successive divisions: • Meiosis
I ‒ Homologous chromosomes separate, reducing chromosome number. • Meiosis II ‒
Similar to mitosis; sister chromatids separate. Significance: Meiosis promotes genetic
variation through crossing over and independent assortment. Text Diagram Description:
Imagine homologous chromosomes pairing and exchanging genetic material before
dividing into four genetically unique cells.
5. Differences Between Mitosis and Meiosis
Mitosis produces two identical diploid cells, while meiosis produces four non-identical
haploid cells. Mitosis occurs in somatic cells; meiosis in gametes. Genetic variation occurs
only in meiosis.
1. Meaning and Importance of Cell Division
Cell division is the process through which a parent cell divides to form two or more
daughter cells. It is essential for growth, repair, and reproduction. In unicellular organisms,
it leads to new individuals, while in multicellular organisms, it enables tissue repair and
growth.
2. The Cell Cycle and Its Phases
The cell cycle consists of two main stages: Interphase and the Division Phase. Interphase
includes G1 (growth), S (DNA synthesis), and G2 (preparation for division). The division
phase includes Mitosis or Meiosis, followed by Cytokinesis.
3. Mitosis ‒ Stages and Significance
Mitosis results in two genetically identical daughter cells. It occurs in somatic (body) cells
and maintains chromosome number. The stages include: • Prophase ‒ Chromosomes
condense and become visible; spindle fibers form. • Metaphase ‒ Chromosomes align
along the cell s equator. • Anaphase ‒ Sister chromatids separate and move to opposite
poles. • Telophase ‒ Nuclear membranes reform, and chromosomes uncoil. • Cytokinesis ‒
Division of the cytoplasm to form two new cells. Text Diagram Description: Imagine two
identical sets of chromosomes separating equally into two new nuclei, ensuring identical
genetic material in each daughter cell.
4. Meiosis ‒ Stages and Significance
Meiosis occurs in reproductive cells (gametes) and reduces the chromosome number by
half, producing four non-identical daughter cells. It has two successive divisions: • Meiosis
I ‒ Homologous chromosomes separate, reducing chromosome number. • Meiosis II ‒
Similar to mitosis; sister chromatids separate. Significance: Meiosis promotes genetic
variation through crossing over and independent assortment. Text Diagram Description:
Imagine homologous chromosomes pairing and exchanging genetic material before
dividing into four genetically unique cells.
5. Differences Between Mitosis and Meiosis
Mitosis produces two identical diploid cells, while meiosis produces four non-identical
haploid cells. Mitosis occurs in somatic cells; meiosis in gametes. Genetic variation occurs
only in meiosis.
