Students will learn about meiosis and its role in sexual reproduction.
After completing this tutorial, you will be able to complete the following:
Sexual reproduction is the joining of the male reproductive cell (the sperm), and the female reproductive cell (an egg) to form a fertilized egg, or zygote. In the process of fertilization, the male and female each donate half of the total genetic material required to form a whole human cell. This is accomplished with one sperm cell and one egg. A human has a total of 46 chromosomes, or 2 sets of 23 chromosomes. One set of 23 chromosomes is donated from that person's father and the other from his or her mother. The zygote will eventually form into a baby that contains only 46 chromosomes due to process called meiosis. Meiosis is the process of cell division that reduces the number of chromosomes.
Meiosis, also called "reduction division," which is the process of reducing the number of chromosomes to half the number found in other cells. If this process did not occur, the chromosome number would double with each fertilization, and after the several generations, the number of chromosomes in each cell would become unfeasibly large. For example, imagine if each parent donated ALL 46 of his or her chromosomes and fertilization occurred. The offspring would have 92 chromosomes.
The number of chromosomes does not keep growing because of the reduction division that occurs in meiosis. Therefore, meiosis and fertilization work together simultaneously to produce cells-generation after generation-with a consistent number of chromosomes.
Meiosis is the process of cell division used to produce sperm and egg haploid cells (cells with only one complete set of chromosomes, i.e., 23 chromosomes). During the process of meiosis, a cell undergoes two divisions, each with half the number of chromosomes of the parent cell. These divisions are called Meiosis 1 and Meiosis 2. Each division consists of four stages: Prophase, Metaphase, Anaphase, and Telophase, which will be discussed below:
Please note, prior to the first stage of meiosis, all chromosomes must grow and duplicate. This is often referred to as Interphase.
|Approximate Time||2 Minutes|
|Pre-requisite Concepts||cells, nucleus, chromosomes, DNA, meiosis, sexual reproduction|
|Type of Tutorial||Concept Development|
|Key Vocabulary||carbon dioxide, cycle, oxygen|