Regulation of cell cycle & Cancer cell Flashcards
What is the main role of checkpoints throughout the cell cycle?
It controls and regulates the cell cycle.
What are two signals that the cell receives from checkpoints?
Stop/Go signals.
What is the most important checkpoint?
G1 checkpoint is the most important checkpoint.
What are some things that should be checked for G1 checkpoints?
Cell size, growth factors, and DNA damage.
What is the key event for the go signal during the G1 checkpoint?
Cell completes whole the cell cycle.
What is the key event for the stop signal during the G1 checkpoint?
Cell enters a nondividing state known as a G0 phase.
What types of cell stays at G0 checkpoint?
Muscle/nerve cells stay at G0 checkpoint.
What are some things that should be checked for G2 checkpoints?
Completion of DNA replication and DNA damage.
What is the key event for the go signal during the G2 checkpoint?
Cell proceeds mitosis.
What is the key event for the stop signal during the G2 checkpoint?
Cell cycle sops and the cell will attempt to repair damage. If damage cannot be repaired the cell will undergo apoptosis (Programmed cell death).
What are some things that should be checked for M checkpoints?
Checks for microtubule attachment to chromosomes at the kinetochores at metaphase.
What is the key event for the go signal during the M checkpoint?
Cell proceeds to anaphase and completes mitosis.
What is the key event for the stop signal during the M checkpoint?
Cell will pause mitosis to allow for spindles to finish attaching to chromosomes.
What are two internal cell cycle regulators?
Cyclins(proteins) and CDKs(enzymes known as cyclin-dependent kinases)
What are the main characteristics of cyclins?
Concentration of cyclins varies.
What are the main characteristics of CDKs?
Concentration remains constant through each phase of the cell cycle.
What are three external cell cycle regulators?
Growth factors, Contact (pr density) inhibition, and anchorage dependence.
What are Growth factors?
They are hormones released by cells that stimulate cell growth.
What is Contact inhibition?
Cell surface receptors recognize contact with other cells.
What is Anchorage dependence?
Cells rely on attachment to other or the extracellular matrix to divide.
How do normal cells become cancerous?
Through DNA mutations normal cells become cancerous.
What are the three traits of normal cells?
They follow checkpoints. They divide on average 20~50 times in culture (in petri dish). Go through apoptosis when there are significant errors.
What are the three traits of cancer cells?
Do not follow checkpoints. They can divide infinitely when in culture (considered to be immortal). Evade apoptosis and continue dividing even with errors.
