Transcript Review of the Cell Cycle

Review of the Cell Cycle
How big is a cell?
Answer
Click below to review or
learn more:
Cell Cycle Animation
Cell cycle checkpoints (three major types of checkpoints)
1. A checkpoint insures that all DNA damage has been corrected
prior to entry into S phase
2. A checkpoint insures that all DNA has been duplicated before
the cell enters into mitosis
3. A mitotic checkpoint ensures that all chromosomes have been
aligned on the metaphase plate before anaphase is allowed to
begin
The cell cycle checkpoints can result in a cell entering
apoptosis(for instance, if there is too much DNA damage to be
repaired ). Apoptosis is programmed cell death that can result
from signals external or internal to the cell. In either case,
proteolytic enzymes called capsases are activated.
Defects in cell cycle checkpoints can lead to a variety of
pathological conditions, including cancer and genetic defects.
.
Click below to review or learn more
about mitosis (in the cell cycle)
Mitosis
Cell Cycle regulation
• Protein molecules called Cyclins
• CDK’s (cyclin dependent kinases)
• 2 types
– Internal regulators – respond to events within
the cell (ex., no mitosis until chromosomes
replicated)
– External regulators – respond to outside
factors and speed up/slow down activity
Cell Cycle regulation
Click below to learn more about
Cancer and the Cell Cycle
Cancer
Cancer therapy targets components of the cell cycle.
Most cancer chemotherapeutic drugs target dividing
cells (and are not specific for cancer cells).
Specific targets are DNA synthesis (S phase) and mitosis
(M phase).
Drugs like Methotrexate (5-fluorouracil; a nucleoside
analog) and Topoisomerase II inhibitors interferes with
DNA synthesis (S phase).
Drugs like vinblastine and Taxol interfere with
microtubule dynamics and mitosis.
DNA damage induced by radiation and chemotherapy
can induce apoptosis
Take the quiz on cell biology
Click for quiz page
"There's an industrial park's
worth of molecular
machinery running the cell
cycle". Paul Nurse in "The
Incredible Life and Times of
Biological cells". Science
289: 1711-1716 (2000)
Happy Trails, pardner!