Cell cycle Flashcards
1
Q
4 separate phases
A
G1 phase-growth phase 1
S phase- synthetic phase
G2 phase-growth phase 2
M phase- mitosis
2
Q
G0
A
- quiescent phase
- cells are stimulated by growth factors (EGF, PDGF, IGF) and results in activation of transcription factors and lead to the initiation of DNA synthesis, followed by mitosis and cell division
- from G0 the cell moves on to G1
3
Q
G1
A
- growth phase 1
- chromosomes are prepared for replication
4
Q
S phase
A
-46 chromosomes are duplicated into chromatids
5
Q
Cell division
A
- process by which cells reproduce
- mitosis
6
Q
Interphase
A
- ‘holding stage’ occurring between two consecutive cell divisions
- replication of cellular genetic material and organelles occurs during interphase
- it is the longest phase and all steps in the cell cycle (ie G0, G1, G2 and S) except M constitute interphase
7
Q
Mitosis
A
Made up of: Prophase Metaphase Anaphase Telophase
8
Q
Prophase
A
- condensation of chromatin to discrete chormosomes
- breakdown of nuclear envelope
- formation of spindles at oppositve cellular poles
9
Q
Metaphase
A
- alignment of chromosomes at the metaphase plate
- equatorial alignment
10
Q
Anaphase
A
- separation of paired chromosomes (sister chromatids)and migration to opposite ends of the cell
- preserves chromosomal numbers
11
Q
Telophase
A
- chromosomes are packed into distinct new nuclei in the emerging daughter cells
- cytokinesis (division of cytoplasm) also starts at this time
- 2 cells produced
12
Q
Meiosis
A
- divided into 2 parts
- meiosis 1 and meiosis 2
- 4 cells produced with each one with half the number of chromosomes of the parent cell
- Meiosis 1 is a reduction division
- main difference is the occurrence of synapsis (crossing over) in the prolonged prophase and non-separation of sister chromatids during anaphase 1
- meiosis 2 is the same as normal mitosis
