Week 3: Cell Cycle Flashcards
What is cell growth?
Increase in cell size (Hypertrophy)
Cell growth is distinct from proliferation.
What is proliferation?
Increase in cell number (Hyperplasia) by cell division occurring faster than cell death
What is the normal rate of cell division for frog embryo cells?
30 minutes
What are the two major events in the cell cycle?
- S-phase (synthesis phase)
- M-phase (mitotic phase)
What occurs during the S-phase of the cell cycle?
Chromosomes duplicate
What happens during the M-phase of the cell cycle?
Duplicated chromosomes segregate into daughter cells
What are the four phases of the cell cycle?
- G1 phase
- S phase
- G2 phase
- M phase
What is Interphase in the context of the cell cycle?
G1, S, and G2 phases combined
What occurs during Interphase?
- Growth
- Performing normal cellular functions
- Duplication of protein content
- Duplication of RNA content
- Duplication of chromatin
- Duplication of organelles
What is the G0 phase?
A resting state where most cells do not divide
What is required for a cell to move from G0 to G1?
Stimulation by growth factors
What is MPF?
Mitosis-promoting factor, a complex of proteins that induces mitosis
What is the role of CDK in the cell cycle?
Master regulator of the cell cycle and a kinase enzyme that adds phosphate groups to amino acids in polypeptides
What are cyclins?
Regulatory subunits that undergo cycles of synthesis and degradation during the cell cycle
List the four classes of cyclins.
- G1/S-cyclin (cyclin E)
- S-cyclin (cyclin A)
- M-cyclin (cyclin B)
- G1-cyclin (cyclin D)
True or False: The cell cycle is free running in early embryos.
True
What is the difference in cell cycle regulation between early embryos and somatic cells?
Early embryos have a free-running cell cycle, while somatic cells have a regulated cell cycle.
During which phase do DNA levels double until cell division occurs?
S phase
What happens to protein and RNA levels during cell division?
They will halve as the cell divides
What role do growth factors play in the cell cycle?
They stimulate cells to enter the cell division cycle
What is the significance of the Nobel Prize awarded in 2001 related to the cell cycle?
It was awarded for discoveries of key regulators of the cell cycle.
Fill in the blank: The G1 phase occurs ______ the S phase.
before
