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01 cell cycle notes


									The Process of Cell
Growth & Division
1.   How is the life cycle of a human and a single cell
2.   How is the life cycle of a human and a single cell
3.   Compare the life of cell to the clock – in 12 hours
     how long does the cell spend actually dividing?
4.   Why do you think cells make a copy of their DNA
     before they divide in half?
5. What do we call DNA that is spread out?
6. What do we call DNA that is coiled up?
7.   Compare the string to DNA. Do you think it is easier for the
     cell to read (and use) the DNA when it is chromatin or
8.   Compare the string to DNA. Do you think it is easier for the
     cell to pass the DNA onto future generations when it is
     chromatin or chromosomes?
 Growth and Regulation
1.   What are the
     two parts of
     the cell cycle?
2.   Summarize
     what occurs
3.   What is the
     mitosis and
Growth and Regulation
4. What is G0?
   What types of
   cells in your body
   are in G0?
Growth and Regulation
 5.   Why do cells divide?
 6.   How many times can a normal cell
 7.   What are the three ways normal growth
      is controlled? Explain each method.
          anchorage dependence
          density-dependent inhibition.
          Proto-oncogenes
Growth and Regulation
 8.    What is a stem cell?
 9.    What is apoptosis?
 10.   Why is apoptosis so important to cells?
A closer look at Eukaryotic DNA
throughout the life of the cell…
     Day-to-day the DNA is coiled around histone proteins into threads.
      VOCAB - chromatin
         Before dividing the DNA replicates (makes an identical copy of itself). The
          chromatin creates an X like structure.
          VOCAB - Chromatid / Centromere

      When dividing the DNA coils even further into short rods.
      VOCAB - chromosomes
    Growth (Interphase)
   G1: Gap 1
       Cell grows bigger and
        makes proteins needed for
   S Phase: DNA Synthesis
       During the S phase, the cell
        replicates its DNA.
   G2: Gap 2
       Cell grows even bigger and
        makes proteins needed for
        two cells!
   Division of the DNA
       Prokaryotes divide in a process called Binary Fission.
       Eukaryotes divide in a process called Mitosis.
Division of a Prokaryotic Cell
   Called Binary Fission
       Chromosomes segregate
        (move to opposite sides
        of the cell)
       Cell Divides
    Flip Your Paper Over
                              INTERPHASE

Division of an Eukaryotic Cell
   There are 2 stages to Division:
       Division of the DNA (MITOSIS)
         1.   Prophase
         2. Metaphase
         3. Anaphase
         4. Telophase
       Division of the cytoplasm (CYTOKINESIS)
                          Think Prepare -
                              The DNA coils into
                              The nucleus
                              Centrioles and
This is a picture of           spindle fibers take
a cell in prophase.            their places
                            Think Middle -
                                Chromosomes line
                                 up at the center of
                                 the cell.
                                Centromeres
                                 becomes attached to
                                 spindle fibers.
This is a picture of a
cell in metaphase.
                          Think - apart
                              Each centromere divides.
                              Sister chromatids separate and
                               move apart.

This is a picture of
a cell in
                          Think - two
                              Two nuclei form and
                               the DNA spreads back

This is a picture of
a cell in telophase.
                            The cytoplasm divides.

This is a picture of
a cell in cytokinesis.
Videos of Division

        http://highered.mcgraw-
        http://www.hybridmedicalanimati
Flip Your Paper Back Over
Cytokinesis in
Animal Cells

Cell’s membrane pinches
inward until the two sides
touch resulting in two
separate daughter cells.
Cytokinesis in
Plant Cells
Cell’s membrane CAN NOT
pinch inward because of the
rigid cell wall. Instead, a cell
plate forms between the
two nuclei and slowly grows
into a new wall separating
the two daughter cells
           G1 phase

                      S phase

G2 phase
Cell Cycle in Onion Cells

   interphase              prophase                metaphase

                anaphase          Telophase / cytokinesis
Focus On Cancer
 1. What is cancer?
 2. What is a tumor?
      Cancer is a disease caused by normal cells changing so
       that they grow in an uncontrolled way. The
       uncontrolled growth causes a lump called a tumor to
Focus On Cancer
 3. How many different types of cancer are there?
 4. Why are there so many types of cancer?
 5. List 5 different types of cancer that you have
    heard of
2010 Cancer Data
2010 Cancer Data
Focus On Cancer
6. How many times can cancer cells divide?
7. Why do scientists describe cancer cells as
   immortal? (two reasons)
8. Why can cancer cells spread while normal cells
   can not?

Approx. 11 min.
   Doctors and scientists now know that each cancer
    starts with changes in one cell or a small group of
   Usually, many years before you can feel a lump, or a
    doctor can see it on a scan, the cells have started to
    reproduce uncontrollably.
   Remember from your earlier assignments that there are
    many differences between normal cells and cancer cells.
       Cancer cells don't die if they move to another part of the body

       Cancer cells don't stop reproducing
       Cancer cells don't obey signals from other cells
       Cancer cells don't stick together
       Cancer cells don't specialize, but stay immature

   This happens because some of the genes in the cell have
    been damaged or lost. Scientists call these changes
Cancer Causes
   Mutations are changes in your DNA. They can occur
    for many reasons
       They can be inherited from your parents (in which case you
        are pre-desposed to having cancer)

       They can occur randomly.
       They can be caused by exposure to something harmful to
        your DNA (a carcinogen) like:
           Cigarette smoke (#1 carcinogen)

           Chewing tobacco

           Asbestos

           UV light

           X-rays
Cancer Causes
   Let’s take a closer look at the types of mutations that
    result in cancer…
Cancer Mutations Table
                         What happens when they mutate…

Proto-oncogenes &        Tell the cell to divide even when it is not necessary
Oncogenes                (Allow cancer cells to ‘cycle’ faster than normal)

                         Turn off the breaking mechanism for cell division (Allow
Tumor Suppressor Genes
                         cancer cells to ‘cycle’ faster than normal(

Apoptosis Genes          Stop apoptosis (Allow mutations to build up in the cell)

                         Stop fixing mutations (Allow mutations to build up in
DNA Repair Genes
                         the cell)

                         Provide cancer with limitless food and O2 (allow tumors
Angiogenesis Genes
                         to grow)

                         Various genes that…Allow the cancer cells to detach
Metastasis Genes
                         and spread throughout the body
Cancer Symptoms
   Cancers can cause different symptoms
    according to where they are in the body. A
    cancer may press on a nerve, or another nearby
    body organ. It may also cause symptoms by
    releasing chemicals or hormones into the
    bloodstream. These effects will eventually
    disrupt normal cell, tissue and organ function.
Cancer Treatments

        There are three major treatment methods for
            Chemotherapy

            Surgery

            Radiation
Chemotherapy – traditional
   Chemotherapy literally means 'drug treatment'. In
    cancer treatment, the term chemotherapy means
    treatment with cell killing (cytotoxic) drugs. A
    person may have just one chemotherapy drug or a
    combination of different chemotherapy drugs. There
    are more than 90 different drugs currently available
    and new ones are being developed all the time.
Chemotherapy – magic bullet drugs
   A newer branch of chemotherapy has recently
    become available for some cancers. These drug
    focus on protein replacement or blockage instead of
    killing cells.
   These drugs have far fewer side effects.
   Examples include:
       Anti-Veg-F – a drug that uses proteins to block
        angiogenesis (results in tumor shrinkage)
       Glevic – a drug that uses a protein to block an
        oncogene (results in slower cell division)
   Surgery is cutting away tissue from the body.
   For some cancers, surgery is the only treatment a
    patient may need. It is likely to cure small, early
    stage cancers that have not spread to other parts of
    the body.
Radiotherapy / Radiation
   Radiotherapy means the use of 'radiation', usually X-rays, to
    treat illness. Doctors have a lot of experience using
    radiotherapy in medicine. About 4 out of 10 people with
    cancer (40%) have radiotherapy as part of their treatment. It
    can be given
       From outside the body as external radiotherapy, using X-rays, 'cobalt
        irradiation', electrons and more rarely other particles such as protons.
       From within the body as internal radiotherapy, by drinking a liquid
        that is taken up by cancer cells or by putting radioactive material in, or
        close to, the tumor.

   Radiotherapy destroys the cancer cells in the treated area.
    Although normal cells are also affected by radiation, they are
    better at repairing themselves than the cancer cells.
Help for your flow chart…
   Start with a healthy cell
                                                     In any order:
   Then show a mass forming – with 1 mutation       oncogene,
   Then show a larger mass of cells with 2          suppressor
    mutations.                                       gene, or p53
   Then show an even larger mass of cells with 3
   Then show an even larger mass of cells with
   Then show the mass spreading via metastasized.
The End

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