Cell Cycle Flashcards
1
Q
Cell cycle
A
A highly regulated series of events that leads to the cells reproduction
2
Q
Biochemical timer
A
A complex series of events regulated by the cell-cycle control system
3
Q
Examples of cell cycle duration
A
- Embryonic cells - 30 minutes
- Intestinal epithelium - 12 hours
- Cultured Fibroblasts - 20 hours
- Liver: Divide ~once a year
- Mature nerve cells: do not divide after maturity. In permanent G0 phase
4
Q
Name the 2 major phases of the cell cycle
A
- Interphase
- Mitotic phase
5
Q
Name the 3 additional phases of the cell cycle
A
- G1 (Growth phase 1)
- S (DNA synthesis phase)
- G2 (Growth phase 2)
6
Q
Name the 4 phase of mitosis
A
- Prophase
- Metaphase
- Anaphase
- Telophase
7
Q
Prophase
A
- DNA already replicated when cell enters prophase
- Nucleolus breaks down
- Chromosomes condense
- Formation of mitotic spindles
8
Q
Metaphase
A
- Breakdown of the nuclear envelope
- Chromosomes attached to the spindles
- Chromosomes align on the spindle equator
9
Q
Anaphase
A
- Sister chromatids separate at centromeres and move to the poles
- Organised central spindle assembles
- Cleavage furrow assembles and poles separate
10
Q
Central spindle
A
- a set of microtubule bundles in anaphase cells that overlap for a short region at their plus ends
- Regulate cleavage furrow and cytokinesis
11
Q
Telophase
A
- Cleavage furrow constricts
- Nuclear envelope reassembles
- Proceeds to cytokinesis – the final separation of the cells
12
Q
Cell cycle control
A
- Intracellular and extracellular signals can regulate cell cycle control.
- Cell cycle can be terminated/blocked at any of the checkpoints
- Cell cycle start is decided on a balance between cyclins and cyclin degrading enzymes
- Cdks are not the limiting factor since they are present at large quantities
