Cells:
Cells What do humans, sharks, and cacti have in common? They have many things in common, such as using energy, growing, and reproducing. One important characteristic they share is that they are all made of cells. All living things are composed of one or more cells. Organisms consisting of one cell are unicellular , while organisms consisting of many cells are multicellular . Cells grow until they reach their size limits, and then they either stop growing or divide. New cells are produced from previously existing cells during cell division. We will now look at different types of cell division.
Types of Cell Division :
Types of Cell Division There are three main types of cell division: binary fission, mitosis, and meiosis. Binary fission takes place in prokaryotes, unicellular organisms that lack nuclei. One cell divides into two identical daughter cells during binary fission. Mitosis occurs in eukaryotes, organisms that have cells with nuclei. When a cell undergoes mitosis, it divides into two identical cells. Mitosis occurs in both unicellular and multicellular organisms, but serves different functions in these organisms. Meiosis is a special type of cell division that occurs in multicellular organisms. Meiosis involves two rounds of cell division and produces four unique cells.
Types of Cell Division:
Types of Cell Division
Cell Division in Unicellular Organisms :
Cell Division in Unicellular Organisms Remember that unicellular organisms consist of only one cell. That one cell divides by undergoing either binary fission if it is prokaryotic, or mitosis if it is eukaryotic. Both types of division serve as a form of asexual reproduction . In asexual reproduction, one organism, the parent, produces a new organism. The new organism is identical to the parent organism. Before the unicellular organism divides, its cell grows in size and its genetic material is copied. The cell splits into two identical cells or, in this case, two identical organisms. Binary fission can occur quickly in bacteria; one bacterium could become one billion bacteria in just a matter of hours. Mitosis generally takes longer to occur, since eukaryotic cells are more complex.
Cell Division in Multicellular Organisms: Mitosis :
Cell Division in Multicellular Organisms: Mitosis Mitosis occurs not only in unicellular organisms, but also in multicellular organisms. The function of mitosis is different in these organisms. Although your body is made of trillions of cells right now, at one time you consisted of just one cell. Cell division was required in order for you to become a multicellular organism. Your growth, as well as that of many other organisms, depends upon cell division. Mitosis creates new cells in multicellular organisms. It allows organisms to grow larger by increasing their total number of cells. It produces body cells, such as skin cells, muscle cells, and bone cells. Another function of mitosis is that it replaces worn out or damaged cells. Some cells, such as skin cells and red blood cells, wear out quickly and need to be replaced. When you cut your finger, it heals because mitosis replaces the damaged cells.
Cell Division in Multicellular Organisms: Meiosis :
Cell Division in Multicellular Organisms: Meiosis A second type of cell division multicellular organisms may undergo is called meiosis. Meiosis occurs in multicellular organisms that reproduce sexually. Sexual reproduction is a form of reproduction in which cells from two parents unite. Meiosis takes place in the reproductive organs, the testes and ovaries. Meiosis is sometimes called gametogenesis since it produces gametes, which are reproductive cells. Males produce gametes called sperm, and females produce gametes called eggs, or ova. Meiosis reduces the chromosome number by half so that when an egg and sperm unite, the offspring has the same number of chromosomes as each of its parents.
What You Learned :
What You Learned You learned that organisms can grow, replace worn out or damaged cells, and reproduce because of cell division. Unicellular organisms use cell division to reproduce asexually. They undergo either binary fission or mitosis. Multicellular organisms undergo a form of cell division called mitosis to grow or to replace cells. They use another type of cell division called meiosis to produce gametes, which are used during sexual reproduction.