Cell division Flashcards
What are the essential features of cell division?
Faithfully replicate genetic material and accurately segregate it into daughter cells.
What are the major phases of the cell cycle?
G1, S, G2, M
What does the mnemonic ‘Go Sally Go Make Children’ stand for?
G1, S, G2, M, Cytokinesis
What are the key regulatory proteins that control the cell cycle?
Cyclin-dependent kinases (CDKs) and cyclins.
How do cyclin-dependent kinases (CDKs) regulate the cell cycle?
By phosphorylating target proteins to drive cell cycle progression.
What discovery earned the Nobel Prize in 2001 related to cell cycle control?
The role of CDKs in regulating the cell cycle.
How is CDK activity regulated?
By phosphorylation/dephosphorylation and protein degradation.
What happens to cells in the absence of the Wee1 kinase?
They divide at a smaller size because Wee1 normally represses division.
What happens to cells in the absence of Cdc25 phosphatase?
They divide at a larger size because Cdc25 normally promotes division.
What is the role of distinct cyclin-CDK complexes?
They control different events in cell division.
What is the function of cell cycle checkpoints?
Ensure conditions are optimal before progressing to the next phase.
What is the role of CDK inhibitors?
They prevent CDK activation if conditions are not suitable for division.
What is the Restriction (R) point, and why is it important?
The G1/S transition, where the cell commits to division.
How does the p53 protein respond to DNA damage?
It directs the transcription of CDK inhibitors to halt the cell cycle.
What are the major events in prophase?
DNA condensation, spindle formation, and nuclear envelope breakdown.
What happens during metaphase?
Chromosomes align at the metaphase plate, and the spindle checkpoint ensures proper attachment.
What is the function of the cohesion complex?
It holds sister chromatids together until anaphase.
What are some diseases associated with cohesion defects?
Roberts Syndrome, a rare genetic disorder.
What happens if the spindle checkpoint fails?
Aneuploidy, leading to abnormal chromosome numbers.
How do anti-mitotic drugs like taxol affect cell division?
They prevent spindle function, causing mitotic arrest and potential cell death.
What are the possible fates of a cell treated with anti-mitotic drugs?
Mitotic death, unequal division, interphase arrest, or resistance.
Why is the degradation of cyclins and securin essential for mitotic exit?
It allows sister chromatids to separate and the cell cycle to proceed.
What are the key structures involved in cytokinesis?
The contractile ring of actin and myosin filaments.
