Please complete the Cell Cycle & Mitosis Tutorial prior to beginning the Meiosis Tutorial.
The goal of this tutorial is for you to learn the stages of Meiosis and describe the important events that occur at each stage. Upon completion of this tutorial, you will also be able to compare and contrast mitosis and meiosis.
Complete all three portions of this tutorial:
1. Read the description of the Meiosis.
2. Watch the animation.
3. Take the quiz.
1. Description of Meiosis
Meiosis is the type of cell division used to produce gametes (sperm and eggs). Meiosis assures that genetic diversity is achieved during sexual reproduction. Meiosis consists of 2 cell divisions: Meiosis I and Meiosis II. Meiosis starts with a diploid (2n) parent cell that divides to make 4 haploid (n) cells. In sexual reproduction, haploid gametes from two different individuals combine to produce a diploid zygote. The resulting offspring is genetically different from both parents.
Haploid (n) = one set of chromosomes
Diploid (2n) = two sets of chromosomes
Eggs and sperm (gametes) are haploid
Diploid set for humans: 2n = 46
Interphase before Meiosis: During the interphase preceding meiosis, DNA replication takes place.
Prophase I: Homologous chromosomes pair up and form tetrads. This pairing is known as synapsis. While paired, the homologous chromosomes exchange genetic material in a process called crossing over. Crossing over contributes to the genetic variation of sexual reproduction. While all this is occurring, the nuclear envelope and nucleoli begin to disappear. Spindle fibers attach to the chromosomes and begin moving them to the equatorial plate.
Metaphase I: Homologous chromosomes, in a pair-wise fashion, have lined up on the equatorial plate. One homologue is positioned on each side of the equatorial plate. The...