Mitosis and The Cell Cycle reproducing cell after cell..

Mitosis The definition of mitosis is part of cellular division in which the nucleus divides It occurs in somatic cells – Somatic cells are all the cells that are not associated with gametes (sex cells).

The 4 Stages of Mitosis In order, they are: – Prophase – Metaphase – Anaphase – Telophase – PMAT (Please Make Another Taco)

The 4 Stages of Mitosis What happens during Prophase: – Chromatin condenses into chromosomes – Centrioles begin to separate – Spindle fibers begin to form – Nuclear membrane begins to break down

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The 4 Stages of Mitosis What happens during Metaphase: – The chromosomes line up in the middle of the cell – Each chromosome is attached to a spindle fiber

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The 4 Stages of Mitosis What happens during Anaphase: – Chromosomes separate to form sister chromatids – Sister chromatids begin to migrate to the poles of the cell

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The 4 Stages of Mitosis What happens during Telophase: – Chromosomes gather at opposite ends of the cell – They lose their distinct shape – Spindle fibers disappear – A new Nuclear Membrane begins to reform at each pole

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Cytokinesis After the cell goes through mitosis, it is quickly followed by cytokinesis – This is the division of the cytoplasm – What actually makes 1 cell into 2 new cells – Mitosis plus Cytokinesis make up the M phase of the cell cycle.

The Cell Cycle

Phases of the Cell Cycle There are 4 phases to the Cell Cycle: – G1 phase – S phase – G2 phase – M phase – Lets take a closer look at each stage..

G1 Phase of Cell Cycle This is a part of Interphase – It is characterized by cell growth – The cell does the majority of it’s growth during this phase – Cells actually divide because they become too large to function at an optimal level. Becoming too large would cause a “DNA overload” The cell’s DNA would no longer be able to serve the increasing needs of the growing cell

S Phase of the Cell Cycle The S phase is characterized by DNA replication – Before the cell splits, it must make a copy of it’s DNA – This is to ensure that both new daughter cells will have exact copies of that particular organism’s DNA – The S phase is also part of Interphase

G2 Phase of the Cell Cycle The G2 phase is the last stage of Interphase. – It is characterized by the preparation for mitosis. – Here the cell has grown to a maximum size, made a copy of it’s DNA – Now the organelles needed for cellular division are produced as the cell prepares for mitosis

M phase of the Cell Cycle The M phase is not a part of Interphase, it is classified under Cell Division – The cell first goes through the 4 stages of mitosis: Prophase Metaphase Anaphase Telophase - Cytokinesis takes place shortly after telophase and the cell division is complete and the cycle begins again.

Picture in book.. Can be found on page 245! There will be a quiz on this exact picture coming up soon!

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