![]() There are many types of organisms that reproduce sexually including plants, animals, and insects. This is “Sexual” reproduction, in which one organism reproduces by crossing with another organism. As the cells divide each new cell receives half the number of chromosomes from the original combination of sperm and egg. These cells are “Gamete” or “Sex” cells and the cells must combine to begin the division process. Meiosis is the production of sperm and egg cells. These cells are referred to as “Autosomal” cells. There are many single-celled organisms which reproduce in this manner including paramecium, bacteria, protozoa, etc… In multi-cellular organisms, mitosis takes place at the cellular level with the reproduction of skin, organ cells, hair, blood cells, etc. Mitosis is the “Asexual” reproduction, in which an organism or cell reproduces itself. This shuffling of genetic material between the maternal and paternal chromosomes during meiosis leads to greater genetic diversity.Mitosis and Meiosis are the processes by which an organism prepares cells to participate in either asexual or sexual reproduction to create an entire organism. During the process, chromosomes can exchange pieces of DNA. During this round, the chromosomes are divided into 23 rods in each of the 4 cells. The two resulting cells contain 23 chromosomes. Once they have found their partner, they line up at the centre of the cell for the first round of division. We have 23 pairs of rods, for a total of 46 chromosomes. ![]() Both copies of the same rod are bound together at the middle to form an X. ![]() During meiosis, the mother cell copies its DNA molecules and condenses them into rods (chromosomes). ![]() Meiosis is similar to mitosis, but it has an extra round of cellular division. Meiosis produces four genetically different cells containing half of the genetic material. DNA in sex cells must undergo another round of division: with 23 chromosomes on one side and 23 chromosomes on the other. But a sex cell can only hold half of the genetic material, since it must unite with the other sex cell to produce a new individual. Regular cells have 23 pairs of chromosomes (for a total of 46 chromosomes), and each pair contains one chromosome from our father and another chromosome from our mother. When sex cells, the sperm and the egg, are involved, cell division is taken to a whole other level! The process is called meiosis. The chromosome pairs then split and move apart toward opposite poles of the cell before it divides into two genetically identical daughter cells. Once the nuclear membrane breaks down, the chromosomes line up in a neat row at the centre of the cell. Both copies of the chromosomes stick together in the middle, which is why they look like an X under the microscope. DNA is then condensed into rod-like structures known as chromosomes. To achieve this, the cell must first make a second copy of all the DNA in its nucleus. The process by which a cell splits into two genetically identical copies is called mitosis. For example, cells are constantly duplicating so that our nails and hair keep growing. (mitosis and meiosis) Our cells reproduce so that we may grow and regenerate.
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