Message Passing and Reproducing in Cells

 This week in AP Biology we reviewed cell to cell communication and the cell cycle. 

 There are three types of cell to cell communication no distance, short distance, and long distance. In no distance communication the cells are touching and can send messages to one another. Plants have holes in there cell wall that allows the message to pass. When there is a short distance in cell to cell communication a local regulator is used to pass on the message, neurotransmitters are an example. When there is a long distance to pass on a message a hormone is used. The hormone is sent all around but only passes the message on to the right cells. 

After we went over cell to cell communication we then went to the cell cycle. The cell cycle is made up of the G1 phase, S phase, G2 phase, mitosis, and cytokinesis. There is also a G0 phase that some cells go into. G1, S, and G2 phase all make up interphase. In G1 phase the cell is working normally as the cell progresses into G2 it starts copying its DNA. When the cell starts S phase it again goes through its normal process. Then the cell gets to mitosis.  When mitosis and cytokinesis are combined it is called the mitosis (m) cycle the first phase is prophase. In prophase the chromatin becomes more clear and thicker and the centrioles become visible. Metaphase follows prophase in which the chromatin which has turned into sister chromatids are lined up in the middle of the cells with the centrioles at opposite ends and the mitotic spindle is forming. Anaphase which is the third phase is when the sister chromatids are pulled apart by kinectchores and nonkinectchores elongate the cell. The fourth and finall stage of mitosis (m) cycle is telophase and cytokinesis which is when the nucleus splits apart and start to reform the nuclear wall. And the cytoplasm splits thus creating another cell identical to its self. 

 To help control mitosis and prevent uncontrollable division there are checkpoints that the cell must pass before it can proceed into different phases. The are also internal and external  mechanisms that help to control uncontrollable division which can lead to cancer.