Lecture 43: Cell proliferation- Mitotic signals Flashcards
Flashcards on Cell Cycle Control
- Q: What are the main phases of the cell cycle?\
A: G1
S
- Q: What happens during the G1 phase?\
A: Cell grows
produces proteins
- Q: What occurs during the S phase?\
A: DNA replication occurs
doubling the genetic material.
- Q: What is the G2 phase responsible for?\
A: Final preparation for mitosis
including protein synthesis and organelle duplication.
- Q: What is the significance of the M phase?\
A: Mitosis and cytokinesis occur
leading to cell division.
- Q: What are the key checkpoints in the cell cycle?\
A: G1/S checkpoint
G2/M checkpoint
- Q: What does the G1/S checkpoint check for?\
A: DNA damage
cell size
- Q: What does the G2/M checkpoint ensure?\
A: Proper DNA replication and damage repair before mitosis.
- Q: What is checked at the spindle assembly checkpoint?\
A: Proper chromosome attachment to the spindle before anaphase.
- Q: What is the role of cyclins in the cell cycle?\
A: They regulate the cycle by activating cyclin-dependent kinases (CDKs).
- Q: What are CDKs?\
A: Cyclin-dependent kinases
enzymes that drive cell cycle transitions.
- Q: How are CDKs regulated?\
A: By binding to cyclins and through phosphorylation/dephosphorylation.
- Q: What is the role of p53 in the cell cycle?\
A: It halts the cycle in response to DNA damage
preventing mutations.
- Q: What happens if p53 is mutated?\
A: Cells can divide uncontrollably
leading to cancer.
- Q: What are mitogens?\
A: Growth factors that stimulate cell division.
- Q: What role does Rb protein play in the cycle?\
A: It inhibits the G1/S transition by blocking E2F transcription factors.
- Q: How is Rb inactivated?\
A: By phosphorylation through CDKs
allowing cell cycle progression.
- Q: What is the function of APC/C?\
A: Anaphase-promoting complex; it degrades cyclins and ensures mitotic exit.
- Q: What role does SCF complex play?\
A: It degrades inhibitors of S phase CDKs
allowing progression.
- Q: What is the function of Cdc25?\
A: A phosphatase that activates CDKs by removing inhibitory phosphates.
- Q: What happens during prophase in mitosis?\
A: Chromosomes condense
and spindle fibers begin forming.
- Q: What occurs during metaphase?\
A: Chromosomes align at the metaphase plate.
- Q: What marks anaphase?\
A: Sister chromatids separate and move to opposite poles.
- Q: What happens in telophase?\
A: Nuclear membranes reform around separated chromosomes.
- Q: What is cytokinesis?\
A: The division of the cytoplasm
completing cell division.
- Q: What is the restriction point in the cell cycle?\
A: A point in G1 where the cell commits to division.
- Q: What are oncogenes?\
A: Mutated genes that drive cancerous cell division.
- Q: What are tumor suppressor genes?\
A: Genes that prevent uncontrolled cell division.
- Q: What is the function of ATM/ATR kinases?\
A: They detect DNA damage and activate checkpoint pathways.
- Q: What is the role of cohesins?\
A: Proteins that hold sister chromatids together until anaphase.
- Q: How does the spindle checkpoint prevent errors?\
A: By blocking anaphase until all chromosomes are attached properly.
- Q: What is the function of separase?\
A: It cleaves cohesins
allowing chromosome separation.
- Q: How does the cell cycle respond to DNA damage?\
A: It activates repair pathways or triggers apoptosis.
- Q: What is contact inhibition?\
A: A mechanism that stops cells from dividing when crowded.
- Q: How do growth factors influence the cell cycle?\
A: They activate signaling pathways that promote division.
- Q: What is the role of Wee1 kinase?\
A: It inhibits CDKs by adding inhibitory phosphates.
- Q: How do CDK inhibitors (CKIs) function?\
A: They bind to CDKs to block their activity and slow the cycle.
- Q: What is the role of Mdm2 in cell cycle regulation?\
A: It degrades p53
controlling its levels in the cell.
- Q: Why is the cell cycle tightly regulated?\
A: To prevent uncontrolled division
mutations
- Q: What is the significance of cell cycle checkpoints?\
A: They ensure accurate division and prevent genomic instability.
