Cell Cycle Flashcards
What are the two primary functions of cell division?
- Reproduction in single-celled organisms 2. Growth, maintenance, and repair in multicellular organisms
What are the four key events that must occur during cell division?
- Reproductive signal 2. Replication 3. Segregation 4. Cytokinesis
What are the two major phases of the cell cycle?
- Interphase 2. Mitotic phase
What occurs during the G1 phase of Interphase?
The cell is biochemically active; change is not evident
What happens during the S phase of Interphase?
DNA synthesis occurs; sister chromatids are formed
What is the purpose of the G2 phase in the cell cycle?
Energy is replenished, organelles reproduce, and cytoskeleton breaks down
What external factors can influence the cell cycle?
- Death of nearby cells 2. Release of growth hormones 3. Cell crowding
What is the G1 checkpoint responsible for?
Checking external influences, cell reserves, size, and genomic DNA damage
What options does a cell have if it does not meet requirements at the G1 checkpoint?
- Stop the cycle and try to fix the problem 2. Enter G0 and wait for better conditions
What does the G2 checkpoint ensure?
Cell size, protein reserves, replication of all chromosomes, and no DNA damage
What is the M checkpoint and when does it occur?
Occurs near the end of metaphase; checks if sister chromatids are correctly attached to spindle microtubules
What are the two groups of intracellular molecules that regulate the cell cycle?
- Positive Regulators 2. Negative Regulators
What role do cyclins play in the cell cycle?
Cyclin levels fluctuate predictably and trigger increases in cyclin-dependent kinase (Cdks) activity
What are tumor suppressor proteins?
Proteins that regulate cell cycle progression and prevent uncontrolled growth
Name three well-known tumor suppressor proteins.
- Retinoblastoma protein (Rb) 2. p53 3. p21
