CELL DIVISION MITOSIS & CYTOKINESIS asexual reproduction produce new individuals Why do cells divide? growth and development from zygote to adult Why do cells divide? repair replace cells destroy by injury Why do cells divide? replacement replace cells that have died Why do cells divide? Skin cells How do cells divide? How many chromosomes in a human cell? Is this a problem???? What can a cell do???? cell divides 4 4 DNA is duplicated 48 Before a cell can divide, it must duplicate/copy its DNA. DNA is duplicated 8 chromosomes 4 chromosomes A cell duplicates its DNA during interphase. one strand of DNA two strands of DNA cell nucleus During interphase, a cell duplicates its DNA. 2 chromosomes 4 chromosomes DNA duplicates How do cells divide? one cell two identical cells 4 chromosomes one cell DNA is duplicated cell divides 8 chromosomes 4 chromosomes Interphase.DNA is duplicated nucleus cell DNA in chromosomes nucleus cell chromosomes in cell 4 chromosomes .single duplicated chromosomes 4 chromosomes ..double DNA is duplicated After Interphase, the cell proceeds to divide. Cell division In eukaryotic cells, cell division involves: 1. Mitosis is division of the nucleus two nuclei is division of the cytoplasm 2. Cytokinesis One cell Two cells one nucleus In eukaryotic cells, cell division involves: 1. Mitosis is division of the nucleus is division of the cytoplasm 2. Cytokinesis One cell Two cells MITOSIS There are four phases in mitosis: 1. prophase 2. metaphase 3. anaphase 4. telophase pmat Remember me! 1. Prophase cell Chromatin condenses into tightly coiled chromosomes. Each chromosome consists of two identical sister chromatids. pro = chromosomes condensed 2. Metaphase Chromosomes line up along the center/middle of the cell. meta = middle 3. Anaphase Sister chromatids separate and are pulled to opposite sides of the cell. Ana = Apart Chromosomes pull apart 4. Telophase The chromosomes have reached opposite ends of the cell Chromosomes begin to uncoil ..form chromatin. The nuclear membrane starts to form. telo = two nuclei Cytokinesis The cytoplasm divides, forming two identical cells. DNA in the form of chromatin The cells can now go about their business. Recap.Making more cells Organisms are always in need of more cells. Organisms make more cells by cell division. Cell division = mitosis + cytokinesis Recap..Mitosis Division of the nucleusMitosis is Recap..Mitosis Which are the phases? PMATPMAT --- prophase --- anaphase --- telophase --- metaphase --chromosomes condensed middle apart two -- chromosomes in middle -- chromosomes move apart -- two nuclei chro Remember me! interphase prophase metaphase anaphase telophase