Chapter 10: Cell Growth and Division - PowerPoint by s981nv

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									Chapter 10: Cell Growth and
Division
 10-1 Cell Growth
 10-2 Cell Division
 10-3 Regulating the Cell Cycle
  Chapter 10 Concept Map            pg. 244-249

  Chromatin                            Gene
                    Chromosomes

                                     Interphase
Sister Chromatids
                    Cell Cycle
                                     Mitosis
 Centromere           Cyclin
                                     Prophase
  Centrioles
                                     Metaphase
  Spindle
                                     Anaphase

     Cell Plate
                      Cytokinesis   Telophase
 Cleavage Furrow
                                                  2
 Chapter 10 Concept Map            pg. 250-252
Results of Mitosis
                       Tissue

                                  Organ

                                           Organ System
     Cancer

               Tumor

Types of Skin Cancer               Melanomas

Squamous Cell Carcinoma

           Basal Cell Carcinoma   Malignant Melanoma
                                                       3
Cell Growth
 Cell size limitations
   Surface area to volume ratio: The volume
    of a cell increases faster than its surface
    area.
       Diffusion: becomes inefficient at moving
        necessary materials in and out of cell when
        volume is too big
     DNA: makes certain proteins necessary to
      all organelles. In a large cell without
      enough DNA, these proteins are not
      produced quickly enough.
       “Information crisis” –cell can’t meet all of its
        needs
                                                           4
Cell Division
  Chromosomes: Condensed clumps of
  DNA that are visible right before cell
  division, they unwind soon after.
      Tightly packed




                                           5
Chromosome Structure
(like a ball of yarn)




                        6
Cell Division
  The Cell Cycle:
  The cycle of
  growth and
  division of a cell
  (interphase and
  mitosis).
  See Figure 10-4,
  pg. 245.
                       7
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Cell Division
Interphase: The growth period of a cell.
  • 3 Parts:
     • G1 : The cell grows in size and carries
       on metabolism (excretion, energy
       production, making proteins).
     • S : DNA replicated in preparation for
       cell division.
     • G2 : Cell parts needed for cell division
       are assembled.


                                                  9
Cell Division
  Mitosis: The phase of the cell cycle
  when the cell begins division; NO
  VARIATION
     Occurs when cell size is at a maximum.
     Occurs in every cell of your body.
     Four distinct phases, or stages.
        Prophase
        Metaphase
        Anaphase
        Telophase
                                               10
Prophase
 First and longest phase of mitosis
 Chromosomes are visible (DNA
 condenses)
 Each half of a replicated chromosome is
 called a sister chromatid.
    They are exact copies of each other
    They are connected by a centromere.
       Scientists are often able to identify
       chromosomes by the location of the
       centromere.

                                                11
Prophase
Nucleus and nucleolus dissolve
    They become no longer visible within the
     cell
By late prophase, centrioles migrate
toward opposite ends of the cell.
    Centrioles: Structures made up of
     microtubules that aid in separation of sister
     chromatids.
      Spindle fibers: many microtubules branching
       out from the centrioles. Created to pull apart
       sister chromatids.
           Plants just have spindle form without the help of
            centrioles.                                         12
 Prophase
                 One Chromosome
Spindle Fibers




  Chromatid             Centrioles
                                     13
Metaphase = middle
  Metaphase: The centromeres on the
  sister chromatids become attached to
  the spindle fibers. The chromatids are
  then lined up in the middle of the cell.
     Each centromere has one spindle fiber on
      either side (one for each chromatid).
        These fibers come from the centrioles.



                                                  14
Metaphase
              One spindle fiber for each chromatid
              that makes up the chromosome




                                     Metaphase in an Onion
   All chromosome line up in the middle             15
Anaphase = away, apart
  Anaphase: the sister chromatids are
  separated
     The centromeres split and the sister
      chromatids are pulled apart.
     The chromatids are pulled by the spindle
      fibers toward the centrioles at the poles of
      the cell.



                                                16
Anaphase
           Chromatids are pulled by spindles, and separate




                                                 17
                                Anaphase in an Onion
Telophase
  Telophase: Phase is characterized by
  cleavage furrow, or cell beginning to split its
  cytoplasm into two distinct daughter cells.
  Chromatids are now far away from each
  other.
     Chromosomes begin to unwind
     Spindle breaks down
     Nucleolus reappears
     Nuclear envelope forms again around
      chromosomes

                                                18
Cytokinesis

 Cytokinesis: Cytoplasm of cell divides.
 Occurs after telophase.
    In a plant cell, a cell plate is laid down to
     separate the contents of the two cells.
     Plasma membranes form inside these new cell
     walls that have been created.




                                               19
Telophase leading into cytokinesis

                     Cell wall formation




                      Telophase into cytokinesis in
                               an Onion 20
I-P-M-A-T
 Interphase
  Prophase
 Metaphase
  Anaphase
 Telophase



              21
Control of the Cell Cycle
 A series of enzymes (cyclins, etc.)
 monitor a cell’s progress from phase to
 phase.
     Enzyme production is directed by genes
     Too many or too few of these enzymes can
      disrupt a normal cell cycle
     Also, the wrong enzyme production can
      disrupt the cell cycle
     Cancer: a disrupted cell cycle; can result
      in excessive cell division
                                               22
Control of the Cell Cycle
  Causes of Cancer
     Environmental factors
       Smoking
               Breast, mouth, lung, pancreatic, liver, etc.
       Exposure to sunlight (UV Radiation)
                 Basal Cell, Malignant melanoma
       Diet
     Genetic Factors
       Faulty genes
       Viral infections
                                                                                             Basal Cell Carcinoma
                                                                                                              23
       http://dermis.multimedica.de/doia/image.asp?zugr=d&lang=e&cd=67&nr=61&diagnr=173922
Types of Skin Cancers
  Basal Cell Carcinoma
     Most common type of skin cancer affecting the
      deepest layer of cells of the epidermis.
  Squamous Cell Carcinoma
     Second most common type of skin cancer.
  Malignant Melanoma
     Most dangerous type of skin cancer arising from
      pigmented areas of the skin.
     Incidents of this cancer have increased among
      young people due to increased sun exposure.

                                                        24
                                       http://www.skincancer.org/skin-cancer/melanoma/melanoma_2.html



 ABCDE of Melanoma:
 asymmetry, border, color, diameter, evolving
                        Benign   Malignant


Symmetrical                                     Asymetrical



Borders are even                                Borders are uneven



One shade                                       Two or more shades



Smaller than 1/4 inch                           Larger than 1/4                          25
Control of the Cell Cycle
  An interesting fact: Where you live is
  also an important factor in cancer rates
     When you move to a different country,
      your chances of getting different kinds of
      cancer change to those in your new
      country.
     The possibility of your getting certain
      cancers is no longer the same as it was in
      your original country
     Cancer Growth Website                      26
Cell Size Limitations Circle Map
 Volume                                       Large
 increases                                    cells
                    Surface area to volume
 faster than                                  without
 surface area:                                enough
 Cell doubles                                 DNA
 in size                                      cannot
 Area                      Cell Size
                          Limitations   DNA   produce
 increases 4x                                 proteins
 Volume                                       fast
 increase 8x
                                              enough
                           Diffusion
Too slow to transport material
                                                    27
in a large cell (BIG volume)
Control of the Cell Cycle Circle Map
                                             Disrupted
Enzyme
production          Enzymes monitor the      cell cycle
                   progress of a cell from   results in
directed by
                      phase to phase.        cancer.
genes.
                        Control of
                         the Cell
                          Cycle

Too many or too
few disrupt cell                             Wrong
cycle                                        enzyme
                                                   28
     Cell Cycle Tree Map
                                       Cell Cycle


Interphase                                                                    Mitosis
Longest phase of the
cell cycle
Growth phase                                   Metaphase        Anaphase
                       Prophase                                                     Telophase
Carries out metabolism                                          Sister          Chromatids at
Chromosomes            1st phase               Chromatids
                                               line up at the   chromatids      opposite ends
duplicated             Longest of mitosis                                     Cleavage furrow
                                               equator          begin to
Cell parts assembled Chromosomes visible                        separate
                                                                                     Cell plate
for cell division      Nucleus/Nucleolus       Attached to                      Two daughter
                                               the              Pulled by         cells formed
                       dissolve                                                   Nucleus and
                                               centromere       spindle
                       Centrioles migrate to                                 nuclear envelope
                                                                fibers                reappear
                       opposite ends of the
                                                                                   Cytokinesis
                       cell
                       Sister chromatids                                           29
Causes of Cancer Tree Map
                Causes of Cancer



Environmental                             Genetic
Smoking                              Faulty genes
Sunlight                           Viral infections
Diet




                                             30
Cell Cycle Flow Chart




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