6.1 - Cell Division

Somatic Cells and Reproductive Cells

• Cell division produces new cells from existing body cells.
• Body cells are divided into somatic cells and reproductive cells or gametes.

Somatic Cells

• Body cells other than gametes.
• Produced through mitosis.
• Diploid ($2n$): Each cell contains two sets of chromosomes.
• Human somatic cells: $2n=46$.

Reproductive Cells (Gametes)

• Reproductive cells.
• Produced through meiosis.
• Haploid ($n$): Each cell contains only one set of chromosomes.
• Human gametes: $n=23$.

Homologous Chromosomes

• A diploid cell contains one set of paternal chromosomes from the male parent and one set of maternal chromosomes from the female parent.
• Paternal and maternal chromosomes with similar structural characteristics form a pair of homologous chromosomes.
• Chromatin: Chromosomes that resemble long, fine threads.

Stages of Cell Division

• Karyokinesis: Division of the nucleus.
• Cytokinesis: Division of the cytoplasm.