Prophase is the first phase of cellular division and occurs in mitosis, meiosis I and meiosis II. In prophase II of meiosis II cell division begins without replication of genetic material.
Centrioles are groups of microtubules that, in both types of cell division, migrate to different poles and attach to chromosomes.
A spindle apparatus is fundamentally comprised of spindle microtubules and hundreds of proteins that, in both types of cell division, helps separate chromosomes during cell division. These spindle apparati attach to the centrioles and the chromatids.
In the beginning of prophase for both types of cell division, the nuclear membrane disintegrates, allowing for splitting of genetic material.
Metaphase is the second phase of cell division and is associated with the alignment of chromosomes at the midpoint between centrioles.
In mitosis, sister chromatids are lined up at the metaphase plate and are ready to be separated into individual chromatids (which are genetically identical).
Anaphase is the third phase of cell division, and is characterized by sister chromatids or homologous chromosomes separating towards opposite poles of the cell.
Tetrads are pulled apart during meiosis I. This is a source of genetic diversity as the chromosome from either parent can be separated into either cell and genetic material exchange has already happened.
Telophase is the fourth phase of cell division and is characterized by the beginning of physical splitting into two daughter cells.
Cytokinesis is the separation of plasma and organelles between each daughter cell, giving each cell the vital components it needs to survive.
In meiosis II, the cells begin as haploid and stay haploid. The original parent cell had one pair of sister chromatids for each chromosome (1-23), but did not have a pair from each parent. Thus, the original cell had double the amount of genetic material in two identical copies. When those identical copies are split into two daughter cells, they, too, only have information from one parent, indicating a haploid to haploid division in meiosis II.
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