9.3 Flashcards
roles of cyclin
The timing and rate of cell division are important, and
controlled by proteins and enzymes.
The cell cycle in eukaryotic cells is driven by a combination of
two substances.
what are cyclins?
Cyclins are proteins that bind to enzymes called
cyclin-dependent kinases (CDKs).
Different cyclin/CDK combinations control different
activities during different stages of the cell cycle.
what is cyclin-dependent kinases (CDK)?
Cyclin-dependent kinases are the families of protein kinases first discovered for their role in regulating the cell cycle.
checkpoints
The cell cycle has built-in checkpoints that monitor the cycle and
stop it if something goes wrong.
There are checkpoints after each stage of interphase to protect
against replicating damaged DNA.
what is cancer?
the uncontrolled growth and division of cells.
Cancer results when cells stop responding to the controls of the
cell cycle.
Cancer cells can kill an organism by crowding out normal cells,
resulting in the loss of tissue function.
what is carcinogens?
Substances that are known to cause cancer.
causes of cancer
Mutations or changes in segments of DNA cause the growth and
division of cancer cells.
Various environmental factors can affect the occurrence of
cancer cells.
Substances that are known to cause cancer are called
carcinogens.
what is apoptosis
the process of programmed cell death.
Cells going through apoptosis shrink and shrivel.
Apoptosis occurs during development in cells that are
damaged or may lead to cancerous growths.
cellular differentiation
the process by which an unspecialized cell develops into a specialized cell with a defined structure and function.
stem cells
a type of cell that can be directed to become a specialized cell.
embryonic stem cells
These are unspecialized cells that result after a
sperm fertilizes an egg.
Each embryonic stem cell has all the DNA needed to
develop into a wide variety of specialized cells.
Embryonic stem cell research is controversial.
adult stem cells
As adults, animals have stem cells that can
differentiate into the specific types of cells they are
surrounded by.
Stem cells are found in various tissues in the body
and might be used to maintain and repair tissue.
Adult stem cell research is less controversial.
