Sexual and Asexual Reproduction

This lesson covers sexual reproduction, asexual reproduction, and the cell division processes of meiosis and mitosis as required by the Edexcel GCSE Combined Science specification (1SC0). You need to compare the two types of reproduction, explain how each type of cell division works and understand their significance.

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Mitosis

Mitosis is the type of cell division used for growth, repair and asexual reproduction. It produces two genetically identical daughter cells, each with the same number of chromosomes as the parent cell.

The Cell Cycle

Before a cell divides by mitosis, it goes through the cell cycle:

1. Interphase — the cell grows, organelles are replicated, and DNA is copied (each chromosome is duplicated to form two identical copies joined at a centromere).
2. Mitosis — the nucleus divides; the chromosomes line up, separate and move to opposite ends of the cell.
3. Cytokinesis — the cytoplasm divides, producing two genetically identical daughter cells.

graph LR
    A["Interphase: cell grows, DNA replicates"] --> B["Mitosis: nucleus divides"]
    B --> C["Cytokinesis: cytoplasm divides"]
    C --> D["2 genetically identical daughter cells"]

Key Features of Mitosis