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Cell Division and Mitosis
Cell Reproduction
Cell division is important because many-called cells, including us, grow because cell division
increases the total number of cells in an organism. Another example where cell division is
important is when billions of red blood cells in our body wear out and are replaced. But not only
is cell division important to many-celled organisms but also to one-celled organisms, as the
amoeba, which use cell division to reproduce.
Cell Cycle
A cell is a living organism. It's life cycle begins with the organism's formation, is followed by
growth and development, and finally ends in death. But the length of a cell cycle is not the same
in all cells. Cells in humans that are needed for repair, growth, or replacement, like the skin and
bone cells, constantly repeat the cycle.
Interphase
The phase of the cell cycle in which the cell spends the majority of its time and performs the
majority of its purposes including preparation for cellular division, is called interphase. Cells in
our body that no longer divide, such as nerve and muscle cells, are always in interphase. Skin
cells which are actively dividing cells, copy their hereditary material and prepare for cell division
during interphase.
- Mitosis: cell process in which the nucleus divides to form two nuclei identical to each other,
and identical to the original nucleus, in a series of steps (prophase, metaphase, anaphase,
and telophase).
- Chromosome: structure in a cell's nucleus that
contains hereditary material.
Each of the trillions of cells in our body, except sex
cells, has a copy of the same hereditary material.
But all of our cells use different parts of the same
hereditary material to become the different types of
cells we are made of.
Mr. Saoulis
Types of reproduction
1. Sexual reproduction: a type of reproduction in which two sex cells, usually an egg and a
sperm, join to form a zygote, which will develop through mitosis into a new organism with a
unique identity.
2. Asexual reproduction: a type o reproduction - fission, budding, and regeneration - in which
a new organism is produced from one organism and has DNA identical to the parent
organism.
MITOSIS
Mr. Saoulis