Transcript Notes - Cancer and Cell Division

Notes - Cancer and Cell Division
FACT: Each minute your body needs to make
about 300 MILLION NEW CELLS!
I. Why Do Cells Divide?
• A cell spends a good part of its life in a "G-phase"
(growth phase) working and growing. However,
cells inevitably wear out, break down and suffer
injuries.
• In addition, as organisms grow and change, they
need new cells to make more skin tissue, bone
tissue, muscle tissue. These new cells can only
come from one place: OTHER CELLS - through the
process of cell division, or mitosis.
II. What is Cancer?
• Cancer is essentially a disease of mitosis the normal 'checkpoints' regulating
mitosis are ignored or overriden by the
cancer cell. When these checkpoints are
ignored, cells can begin to divide out of
control.
Checkpoint:
Cell is normal  Cell moves to next stage of cycle
Cell is damaged  Cell does NOT move to next stage of the cycle.
Cell “kills itself” - apoptosis
III. What Causes Cancer?
• Often cancer is caused by a DNA mutation that
occurs in one of several genes that normally
function to control cell division.
• Example:
The TP53 gene, the “tumor suppressor gene",
usually functions to control the cell cycle.
However, TP53 is mutated in over 50% of all
human cancers.
IV. What are the two types of
tumors?
• Tumors can be either malignant or benign.
Malignant tumors can be fatal because
these tumors rob the body of vital
nutrients and oxygen.
• Malignant tumors can also disrupt the
functioning of organs that they are in, or
spread to other organs by metastasis.
As the tumor grows larger, it begins to release proteins
from the cell to attract new blood vessel growth.
(this is called angiogenesis)
Metastasis
Metastasis
V. What can you do to prevent
cancer?
• DNA damage can be caused by
carcinogens such as cigarette
smoke, UV rays, and pesticides.
• Avoiding exposure to carcinogens
can lower your risk of cancer.
• However, some people are
genetically predisposed to cancer
(it runs in their family).
VI. How do you treat cancer once
you have it?
• There are many ways to treat cancer
including chemotherapy, radiation, and
prescription drugs.
• Many cancer drugs target cells that are
dividing by mitosis. As a result, some
healthy cells usually die as a result of these
treatments.