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Warm Up. You began life as a single cell, and now you are approximately 75 trillion cells! How did that happen?. Cell Reproduction. Chapter 6 – Bio 1-2 Book (Blue). All Cells come from Cells.
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Warm Up You began life as a single cell, and now you are approximately 75 trillion cells! How did that happen?
Cell Reproduction Chapter 6 – Bio 1-2 Book (Blue)
All Cells come from Cells • The division of cells into more cells enables living things to repair damage, to grow and to produce offspring.
Repair & Growth • You are made of 75-100 Trillion Cells! • Your cells continually need to be replaced, they wear out. • Digestive Tract – few days • Immune system cells – 6 weeks • Pancreatic Cells – 1 year
The Cell Cycle: Prokaryotes – no nucleus • Binary Fission: • Cell division in a single celled organism produces two genetically identical organisms. • Asexual Reproduction • Circular Chromosome- See video
What part of the cell is our focus? The nucleus!
The Cell Cycle: Eukaryotes (with a nucleus) • Chromatin: • DNA wrapped around protein • Chromosome: • Chromatin made compact for cell division. • Sister Chromatids: • Two identical chromosomes joined together. • Centromere: • The region where two chromatids join. Chromosome
The Cell Cycle: Interphase • Cells spend 90% of their time “living” and growing. • The period of growth between divisions. • DNA is replicated when cell is triggered to begin reproduction. “INITIAL”
Cell Cycle: Mitotic Phase • Mitosis is divided into four phases: • Prophase • Metaphase • Anaphase • Telophase • New Cell Structures: • Centrioles (animal only) • Spindle Fibers
Warm Up or Closure! • What is a chromosome made of? • Where are chromosomes found? • What is the “initial” or living stage of a cell called?
Mitosis Animation • http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__mitosis_and_cytokinesis.html • Song: http://www.youtube.com/watch?v=pOsAbTi9tHw
Cell Cycle: Mitotic Phase • Prophase: • 1st phase of mitosis • Replicated chromosomes become visible. • The nuclear envelope breaks down and spindle fibers begin to form. • A pair of centrioles help to organize the spindle fibers. PREPARE
Cell Cycle: Mitotic Phase • Metaphase: • 2nd phase of mitosis • Chromosomes line up at the center of the cell. • Spindle fibers connect to the centromeres of each chromosome to the spindle. MEET IN THE MIDDLE
Cell Cycle: Mitotic Phase • Anaphase: • 3rd phase of mitosis • Centromeres split, and the sister chromatids separate. • A complete set of chromosomes move to the opposite sides of the cell. APART
Cell Cycle: Mitotic Phase • Telophase: • 4th (final) phase of mitosis • Chromosomes spread out into chromatin. • The nuclear envelope reforms around each group of chromosomes. • Spindles break apart. MAKES TWO
Cell Cycle: Cytokinesis • Mitosis produces two nuclei, each with a complete set of chromosomes. • Cytokinesis completes the cell division by splitting one cell into two daughter cells. PLANT CELL ANIMAL CELL
Warm Up or Closure! • What is the “initial” or living stage of a cell called? • What phase is when the chromosomes “meet in the middle” of the cell? • What phase “makes two” new nuclei?
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Regulating the Cell Cycle • How do cells know when to divide? • Cells use proteins to regulate the cell cycle. • Some cells respond to outside signals: • When one cell touches another they will stop dividing. • Used in healing. • Some cells use internal signals: • Internal proteins regulate the timing of the cell cycle.
Cancer: Uncontrolled Cell Growth • Cancer develops when the body loses the ability to control growth in some of its cells. • Cancer forms a mass called a tumor. • Cancer cells can metastasize – or form secondary growths elsewhere in the body. • Cancer cells are called malignant – meaning they invade normal tissues. • Benign tumors are not cancerous. They do not spread to other body parts or come back after being removed. • See video
http://learn.genetics.utah.edu/content/health/history/cancer/http://learn.genetics.utah.edu/content/health/history/cancer/