Mitosis Mitosis Essential Questions • • • • How do somatic cells reproduce? What is the purpose of mitosis? What are the names of the phases of mitosis? How do interphase and cytokinesis relate to mitosis? • What happens in each of the four phases of mitosis? Mitosis: the process by which a somatic cell replicates itself -The purpose of mitosis is to produce two daughter cells which are identical to the parent cell Somatic cell reproduction • Interphase • Phases of mitosis – – – – Prophase Metaphase Anaphase Telophase • Cytokinesis Interphase takes place before mitosis starts. Interphase: The cell grows The cell duplicates its DNA Before Mitosis: Interphase: The cell grows The cell duplicates its DNA Chromatin (A piece of DNA before it’s duplicated) Normal nucleus with two pieces of chromatin Phases of Mitosis: Before Mitosis: Interphase: The cell grows The cell duplicates its DNA Chromatin (A piece of DNA before it’s condensed and duplicated) Normal nucleus with two pieces of chromatin Nucleus with condensed, duplicated DNA 1. Chromosome: the entire duplicated, condensed chromatin *DNA is duplicated in interphase but not condensed until prophase 2. Chromatid: one of the two identical copies of DNA that makes up the chromosome Nucleus with duplicated DNA 3. Centromere: holds together two sister chromatids Somatic cell reproduction • Interphase • Phases of mitosis – – – – Prophase Metaphase Anaphase Telophase • Cytokinesis The division of the cytoplasm P. 257: 1-7 1. Certain cyclin proteins regulate mitosis and the cell cycle by allowing or stopping cell cycle processes. 2. It is shorter; cancer cells divide in an unrestrained way. 3. Cigarette smoke, UV radiation, asbestos, etc. 4. In apoptosis, a cell undergoes programmed cell death; cancer cells can grow and divide unrestrained as long as they are supplied with essential nutrients. P. 257: 1-7 5. Stem cells can be used to cure diseases. 6. Embryonic stem cells are found in living human embryos; adult stem cells are found in already developed tissues. 7.The DNA damage would cause the cell to be unable to perform its correct function. Somatic cell reproduction • Interphase • Phases of mitosis – – – – Prophase Metaphase Anaphase Telophase • Cytokinesis Before Mitosis: Interphase: Phases of Mitosis: 1. Prophase: Chromatin is condensed into chromosomes Nuclear membrane disappears Before Mitosis: Interphase: Phases of Mitosis: 1. Prophase 2. Metaphase Chromosomes line up along the middle of the cell Spindle fibers form between centromeres and centrioles -Spindle fibers: rope like structures that separate sister chromatids -Centriole: the organelle from which spindle fibers develop Before Mitosis: Interphase: Phases of Mitosis: 1. Prophase 2. Metaphase Chromosomes line up along the middle of the cell Spindle fibers form between centromeres and centrioles Before Mitosis: Interphase: Phases of Mitosis: 1. Prophase 2. Metaphase 3. Anaphase Sister chromatids are pulled to opposite sides of the cell Before Mitosis: Interphase: Phases of Mitosis: 1. Prophase 2. Metaphase 3. Anaphase 4. Telophase A new nuclear membrane forms around the chromosomes at each end of the cell Chromosomes expand back into chromatin Before Mitosis: Interphase: Phases of Mitosis: 1. Prophase 2. Metaphase 3. Anaphase 4. Telophase Before Mitosis: Interphase: Phases of Mitosis: 1. Prophase 2. Metaphase 3. Anaphase 4. Telophase -The term “mitosis” technically involves only the division of the cell’s nucleus After mitosis: -Cytokinesis: the division of the cell’s cytoplasm What is Cytokinesis • This Is the last stage of the cell cycle & it completes the process of cell division. • During Cytokinesis the cytoplasm divides and organelles are distributed into each of the new cells. Cytokinesis in animal cells • During cytokinesis in animal cells the cell membrane squeezes together around the middle of the cell • Each daughter cell gets about 1/2 of the organelles. Cytokinesis in plant cells • The plant cell t can’t squeeze together like the cell membrane can. • Instead a structure called the cell plate forms across the middle of the cell and the cell gradually splits into two cells. • Then two new cell walls form More info • When cytokinesis is complete two new cells (daughter cells) have formed. • At the end of cytokinesis each cell enters interphase and the cell cycle begins. Cytokinesis in a animal cell. The arrow’s point out the cell membrane seperating Mitosis Flip Book Today, you will begin working on your mitosis animation flip book. Interphase correctly drawn Interphase correctly annotated Prophase correctly drawn Prophase correctly annotated Metaphase correctly drawn Metaphase correctly annotated Anaphase correctly drawn Anaphase correctly annotated Telophase correctly drawn Telophase correctly annotated Cytokinesis correctly drawn Cytokinesis correctly annotated Color included 2 pts Effort 2 pts Title page 2 pts 2 pts 2 pts 2 pts 2 pts 2 pts 2 pts 2 pts 2 pts 2 pts 2 pts 2 pts 2 pts Mitosis Essential Questions • • • • How do somatic cells reproduce? What is the purpose of mitosis? What are the names of the phases of mitosis? How do interphase and cytokinesis relate to mitosis? • What happens in each of the four phases of mitosis? Mitosis Essential Questions • How do somatic cells reproduce? Through the process of mitosis • What is the purpose of mitosis? To make daughter cells that are identical to the parent cell • What are the names of the phases of mitosis? Prophase, Metaphase, Anaphase, Telophase • How do interphase and cytokinesis relate to mitosis? They are not a part of mitosis. Interphase happens before mitosis; cytokinesis happens after. • Prophase Phases of Mitosis – Chromatin is condensed into chromosomes – Nuclear membrane disappears • Metaphase – Chromosomes line up along the middle of the cell – Spindle fibers form between centromeres and centrioles • Anaphase – Sister chromatids are pulled to opposite sides of the cell • Telophase – A new nuclear membrane forms around the chromosomes at each end of the cell – Chromosomes expand back into chromatin