If I started like that, how did I get to this?

CELL CYCLE Over time, organisms grow; many cells die and need to be replaced. The process in a cell’s life cycle when it reproduces to create two identical cells is called mitosis.

Cells formed during mitosis are known as daughter cells.

The cell division process occurs as four different stages, known collectively as the 'cell cycle'.

Cell Cycle The cell cycle consists of four stages – G1 (Growth 1 Phase) – S (Synthesis Phase) – G2 (Growth 2 Phase) – M (Mitotic Phase) The first three phases, as a group, are called Interphase. Cells spend the majority of their life in this stage.

Cell Cycle Interphase - G1 ‘Gap/Growth' phase in which the cell grows and duplicates internal organelles (not DNA).

Cell Cycle Interphase - S is the phase when new DNA is synthesized through DNA replication.

Cell Cycle Interphase – G2 ‘Gap/Growth' phase in which the cell grows and checks duplicated DNA for any errors.

Cell Cycle Mitosis - M is the mitotic phase in which the cell physically divides into two daughter cells.

Mitosis Mitosis is a process where cells are produced for growth and/or replacing damaged or old cells Mitosis has four sub-phases: – Prophase – Metaphase – Anaphase – Telophase

PROPHASE Chromosomes condense, the nuclear membrane breaks down, and spindle fibers form from centrioles.

METAPHASE Replicated chromosomes line up in the middle of the cell. Spindle fibers attach to the centromere of each chromosome.

ANAPHASE Chromosomes begin to be pulled apart, and the cell becomes elongated, with distinct ends (poles).

TELOPHASE Nuclear envelope/membrane re-forms around the separated chromosomes and cell membrane begins to create two independent cells.

CYTOKINESIS The final division of the cytoplasm that completes the process of mitosis and makes two complete daughter cells. ANIMAL CELLS – Cell membrane pinches in to create two equal parts with one nucleus in each daughter cell. PLANT CELLS – Cell plate forms down center of cell between the two nuclei and creates a new cell wall

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Regulating the Cell Cycle Proteins called cyclins regulate the timing of the cell cycle. – These proteins “tell” the cell when it is time to divide. Cancer - disorder when cells lose the ability to control their growth and form clusters of irregular cells called tumors. Cancer & The Cell Cycle Normal vs. Cancer Cell Growth

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CYTOKINESIS

PROPHASE

ANAPHASE