module 10

• The science that study cells is Cytology.
• Cell division accomplishes the increase in the number of cells. Cell divides to give rise to new ones, to replace those old and injured cells and to promote growth of organisms. During development from stem to fully differentiated, cells in the body alternately divide (mitosis) and "appear" to be resting (interphase).
• cell cycle is an orderly sequence of events that describes the stages of a cell's life from the division of a single parent cell to the production of two new cells daughter cells.
• The mechanism involved in the cell cycle are highly regulated and involves two major types: Mitosis and Meiosis
• GAP 0 phase are times when a cell will leave the cycle and quit dividing. It means that if the cell does not receive "go-ahead" signal, it will exit the cell cycle and switch to a non-dividing stage. This may be temporary resting period or more permanent. An example of this is the neuron in the brain, it is cell thathas reached an end stage of development and will no longer divide.
• Gap 1 phase also known as restriction point. On this phase, cell increase in size, produce RNA and synthesize protein. An important cell cycle control mechanism activated during this period; it ensures that everything is ready for DNA synthesis.

  -Ensures that the cell is large enough to divide and that enough nutrients are available to support the resulting daughter cells and most importantly it ensures that DNA is ready for synthesis.
• S phase that produce two similar daughter cells, the complete DNA instructions in the cell must be duplicated. DNA replication occurs during this phase
• Gap 2, on this phase the gap between DNA synthesis and mitosis, the cell will continue to grow and produce new proteins. this checkpoints ensures that DNA replication in S phase has been successfully completed.
• interphase. On this phase, cells may appear inactive but they are quite the opposite This is the longest of the complete period of the complete cell cycle during which DNA replicates, the centrioles divide, and proteins are actively produced.