Cell Division: Mitosis and Meiosis
This page provides an overview of cell division processes, focusing on mitosis and meiosis. It explains the purposes of cell division, the stages of mitosis in cell division, and introduces the concept of meiosis in sexual reproduction.
Mitosis
Mitosis is a process of cell division that results in two identical daughter cells. The purposes of mitosis include:
- Organism growth
- Cell repair
- Asexual reproduction in some organisms
- Cloning in plants
Definition: Mitosis is the process of cell division that produces two genetically identical daughter cells from a single parent cell.
Stages of Mitosis
The 4 stages of mitosis are as follows:
- Prophase mitosis: Chromosomes condense and become visible, and the nuclear membrane disappears.
- Metaphase: Chromosomes align at the cell's equator.
- Anaphase of mitosis: Chromosome copies are pulled to opposite poles of the cell.
- Telophase of mitosis: New nuclear membranes form around the separated chromosomes.
Highlight: Interphase, while not a stage of mitosis itself, is an important part of the cell cycle where DNA replication occurs in preparation for mitosis.
A stages of mitosis diagram is provided, illustrating the process from interphase through cytokinesis.
Meiosis
Meiosis is introduced as a process of sexual reproduction that produces genetically different cells.
Definition: Meiosis is a type of cell division that produces haploid gametes, each containing half the number of chromosomes as the parent cell.
Key points about meiosis include:
- Occurs mainly in testes and ovaries to produce gametes
- One diploid cell produces four haploid gametes through two divisions
- In humans, each gamete contains 23 chromosomes
Vocabulary: A zygote is the cell formed when two gametes fuse during fertilization.
The page also touches on genetic variation, explaining that it results from a combination of genes and environmental factors.
Example: Eye color and blood type are examples of genetic traits, while accents and language are influenced by the environment.
