Cell Reproduction

Cell Reproduction

Introduction to Cellular Reproduction

This guide is designed to provide you with an overview of the important processes involved in the reproduction of cells. Cellular reproduction is a process by which cells duplicate their contents and then divide to yield two cells with similar, if not duplicate, contents. Understanding this process is helpful in understanding the basis for human reproduction as well as the basis for the generation of life in other classes of organisms. Cell reproduction does not always result in new independent cells. It is also essential to growth and development as well as in the day-to-day maintenance of many human cells.

We will be discussing two different types of cell reproduction--mitosis and meiosis. These processes are responsible for creating two different types of cells. Mitosis is a process that creates a nearly exact copy of the original cell. Somatic cells, which include nearly all human cells, are created by this process. Meiosis is a different form of reproduction that leads to the production of germ cells, or sex cells. All cells fall into one of these two categories, which we will discuss in depth in the coming SparkNotes on Cell Reproduction. Some organisms, such as bacteria and single-celled organisms, use only mitosis for cell reproduction.

The difference between mitosis and meiosis can also be thought of as the difference between sexual and asexual reproduction. Humans obviously reproduce sexually, but this is not true for all organisms. Many lower-order cells create entirely new organisms with each round of mitosis: asexual reproduction. In humans and other organisms that reproduce sexually, meiosis is needed to take into account the genetic contribution of the two parent organisms.

This SparkNote will provide a general introduction to cell division and cell reproduction as well as introduce some terms that will ease our understanding of mitosis and meiosis.

Terms

Cell cycle - A repeated process in which cells copy their contents and then divide into two. Occurs in cells as a means of reproduction.

Diploid number - The total number of chromosomes present in a cell.

Gametes - Cells with the haploid number of chromosomes. Gametes are created out of germ cells. The sperm and eggs involved in sexual reproduction are gametes.

Germ cell - Cells that lead to the production of gametes. Produced by meiosis.

Haploid number - The number of unique chromosomes or homologous pairs in a cell. Half the diploid number.

Homologous pair - Refers to two similar chromosomes in a diploid cell. One chromosome is derived from the father gamete cell and the other from the mother gamete.

Meiosis - A type of cellular reproduction that results in the formation of four haploid cells from one diploid cell. Contains two cellular divisions that follow only one round of DNA replication. The type of reproduction that produces germ cells.

Mitosis - A type of cellular reproduction that results in the formation of two identical diploid