7.3 Cell Cycle Dysregulation and Apoptosis Part 2 Flashcards
What is needed at the G2/M checkpoint?
DNA replication and repair must be completed
What is needed at the M checkpoint?
spindle fibers must be fully form and attached to the kinetochore/centromere system
What two classes of proteins monitor the progression of the cell cycle?
cyclins
cyclin dependent kinases
What happens when a cyclin is expressed?
binds to a CDK and induces activation of a cyclin/CDK complex
What does the cyclin/CDK complex do?
phosphorylates and activates other proteins that are needed for the next round of the cell cycle
When are cyclin D complexes expressed?
expressed early in G1 and last throughout most of the cell cycle
What is the function of the cyclin D complexes?
responsible for the transcription of gene products that are needed for DNA replication
When do cyclin B complexes accumulate?
during G2 and peak during M
What is the function of the cyclin B complex?
phosphorylate proteins that induce early mitosis such as nuclear breakdown and chromosome condensation
When must the cyclin B complexes be degraded?
prior to mitosis completing
What do the genes that express cyclins in cancer cells do?
they are expressed at the wrong time or at uncontrolled levels
What allows for the rapid accumulation of mutations in cancer cells?
DNA damage is not repaired before proceeding on to the next phase in the cell cycle
What is apoptosis?
programmed cell death
When is apoptosis important?
during embryonic and early development
What is an example of apoptosis in embryonic development?
eliminating webbing and tail before birth
