Mitosis

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Mitosis
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Mitosis

• Cells divide to make more cells. While all the
  other organelles can be randomly separated into
  the daughter cells, the chromosomes must be
  precisely divided so that each daughter cell gets
  exactly the same DNA.
• Mitosis is normal cell division, which goes on
  throughout life in all parts of the body.
• Mitosis occur in eukaryotes. Prokaryotes use a
  different methodfission to divide.

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Mitosis Video

• Animation

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Cancer

• Cancer is a disease of uncontrolled cell
  division. It starts with a single cell that
  loses its control due to a genetic mutation.
  That cell starts dividing without limit, and
  eventually kills the host.
• Normal cells are controlled by several factors.
• Normal cells stay in interphase until they are
  given a specific signal replicate DNA and the
  cell prepares for division. Cancer cells enter
  replication without waiting for a signal.
• Normal cells are mortal. This means that they
  can divide about 50 times and then they lose the
  ability to die. Cancer cells escape this process
  of mortality they are immortal and can divide
  endlessly.

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Cancer Progression

• Once a single cell starts growing uncontrollably,
  it forms a tumor, a small mass of cells.
• A tumor with a blood supply will grow into a
  large mass. Eventually some of the cancer cells
  will break loose and move through the blood
  supply to other parts of the body, where they
  start to multiply.

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Cancer Treatment

• Two basic treatments surgery to remove the
  tumor, and radiation or chemicals to kill
  actively dividing cells.
• It is hard to remove all the tumor cells. Tumors
  often lack sharp boundaries for easy removal, and
  tumors can be very small and anywhere in the
  body.
• Radiation and chemotherapy are aimed at killing
  actively dividing cells, but killing all dividing
  cells is lethal you must make new blood cells,
  skin cells, etc. So treatment must be carefully
  balanced to avoid killing the patient.

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DNA Replication

• How DNA gets copied
• animation

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Pop Quiz

• Take out a sheet of paper
• And your cell drawings

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Question 1

• What stage does the nuclear membrane disappear
  and the chromosomes become visible?

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Question 2

• What stage of mitosis has the chromosomes in a
  line?

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Question 3

• What stage does the nuclear membrane reform?

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Question 4

• What stage does the chromosome halves
  (chromatids) separate?

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Question 5

• What stage follows telophase and is where the
  cells spends the majority of its life?
• Switch papers with a neighbor

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Answers

• 1 What stage does the nuclear membrane
  disappear and the chromosomes become visible?
• PROPHASE
• What stage of mitosis has the chromosomes in a
  line?
• METAPHASE

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• 3 What stage does the nuclear membrane reform?
• TELOPHASE
• What stage does the chromosome halves
  (chromatids) separate?
• ANAPHASE

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• 5 What stage follows telophase and is where the
  cells spends the majority of its life?
• INTERPHASE