Phases of Meiosis Overview

Study Notes

Prophase 1
- Homologous chromosomes pair up to form a structure known as a tetrad.
- Crossing over occurs, allowing for genetic recombination and exchange of genetic material between homologs.
Prophase 2
- Nuclear envelope disintegrates again, preparing for the second meiotic division.
- Spindle apparatus is reestablished, ready for chromosome alignment.
Metaphase 1
- Homologous chromosome pairs align along the equatorial plane of the cell.
- Spindle fibers attach to the kinetochores of the chromosomes.
Metaphase 2
- Individual chromosomes, not in homologous pairs, line up along the cell's equator.
- Ensures that each daughter cell will receive one copy of each chromosome.
Anaphase 1
- Spindle fibers pull homologous chromosomes apart, moving them toward opposite poles.
- Each pole receives a complete set of chromosomes, although each chromosome still consists of two sister chromatids.
Anaphase 2
- Sister chromatids are separated and pulled apart by spindle fibers.
- Each chromatid is now considered a separate chromosome.
Telophase 1
- Cytoplasm divides through a process called cytokinesis, resulting in two daughter cells.
- Each daughter cell has half the number of chromosomes as the original cell.
Telophase 2/Cytokinesis
- Nuclear membranes reform around each set of chromosomes.
- Cytoplasm divides, producing four genetically distinct daughter cells, each with a haploid set of chromosomes.