The Cell Cycle and Mitosis Mr. Meringolo
The Cell Cycle • The cell cycle is divided into three stages: interphase, mitosis, and cytokinesis. • During the cell cycle, a parent cell divides into two cells. The new cells are identical to the parent cell.
Why do cells divide? Reproduction –Cell division is important for asexual reproduction, which involves only one parent organism. Sexual reproduction involves two parents. In single-celled organisms, the parent cell divides into two identical offspring.Growth and Repair- One characteristic of all livings things is growth. Most growth occurs in organisms happens because cell division produces new cells.
What happens to genetic material during cell division? • DNA- The genetic material in cells that contains the information that determines the traits that a living thing inherits. • DNA contains the instructions for an organisms growth, development, and activities. • Chromatin- A complex material consisting of DNA and proteins • Chromatid- Two identical structures that develop after a chromosome duplicates. • Centromere- Holds the chromatids together.
Mitosis • Mitosis- The part of the cell cycle during which the nucleus divides • Prokaryotes do not undergo mitosis because they do not have a nucleus • Mitosis results in two identical nuclei that are identical to the original nucleus • At the end of Mitosis, the cell has two identical sets of chromosomes intwo separate nuclei. 5
The Phases of Mitosis • Interphase • Prophase • Metaphase • Anaphase • Telophase & Cytokinesis
Interphase occurs before mitosis begins • The part of the cell cycle during which the cell is not dividing • During Interphase, the cell grows to about twice the size it was when it was first produced and produces various organelles. • Changes that occur during interphase prepare a cell for division. • DNA is duplicated during interphase CELL MEMBRANE Nucleus Cytoplasm
Interphase Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Prophase 1st step in Mitosis • Mitosis begins (cell begins to divide) • During prophase, the chromatin in the nucleus of a cell condenses and becomes visible and the membrane around the nucleus begins to break down.
Prophase Plant Cell Animal Cell Spindle fibers Centrioles Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Metaphase 2nd step in Mitosis • During Metaphase, chromosomes line up in the middle of the cell. The Centromeres of the chromosomes are the same distance from each side of the cell.
Metaphase Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Anaphase 3rdstep in Mitosis • During Anaphase, the chromatids separate and they are pulled to opposite sides of the cell. Each side of the cell ends up with a complete set of chromosomes.
Anaphase Plant Cell Animal Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
Telophase 4th step in Mitosis (Last Phase) • The last phase of mitosis • A new nuclear membrane forms around each group of chromosomes and the cell has two identical nuclei. • Chromosomes become less condensed • Cytokinesis begins during this phase
Telophase Animal Cell Plant Cell
Cytokinesisoccurs after Mitosis • Cytokinesis- the division of the parent cell’s cytoplasm. Occurs when the cell membrane pinches inward towards the new nuclei until two complete cells are formed. • Begins during the last step of mitosis
IPMATC REMEMBER! • Interphase • Prophase • Metaphase • Anaphase • Telophase • Cytokinesis IPreferMeatloafAtTennisCamp