Cell cycle and cell division (Short notes)
Feature of cell cycle -coordinated process, under genetic control, observed in eukaryotes, changes occur
in nucleus and Cytoplasm
1.Phases of cell Cycle – interphase and M-phase
Interphase -Phase between two successive M phases, Resting phase, 95% of the duration of cell cycle.
G1 + s + G2
Phase Changes Amount of Ploidy Time
DNA in
diploid cell
Growth, cell size increase, transcription and 2c 2n 33 to 45
translation occur to make enzymes for growth percent
G1 Cell enter from G1 to S phase or G0 phase or
become permanent
DNA Replication occur, Centriole double in animal Change 2n 25-33
S cell in cytoplasm, histone synthesis, Euchromatin from 2c to percent
replicate first 4c
Cell prepare for divisions; Tubulin protein synthesis 4c 2n 15
G2 occur percent
Time- Sequence – G1>S>G2>M (according to time) (human cell -24-hour, yeast cell -90 min
Quiescent stage (G0)- do not divide further exit G1 phase, metabolically active, no longer
proliferate or grow unless require by organism (cell is living)
- Some cells in the adult animals do not appear to exhibit division (e.g., heart cells and neuron)
M Phase-Actual cell division, mitosis occurs, 5%-time, M-phase - karyokinesis + cytokinesis, most
dramatic period, equational division- number of chromosomes in the parent and progeny cells is the same
Occur in – haploid cell (plants and some animals like egg to drone) Diploid cell (plants and animals)
Feature of cell cycle -coordinated process, under genetic control, observed in eukaryotes, changes occur
in nucleus and Cytoplasm
1.Phases of cell Cycle – interphase and M-phase
Interphase -Phase between two successive M phases, Resting phase, 95% of the duration of cell cycle.
G1 + s + G2
Phase Changes Amount of Ploidy Time
DNA in
diploid cell
Growth, cell size increase, transcription and 2c 2n 33 to 45
translation occur to make enzymes for growth percent
G1 Cell enter from G1 to S phase or G0 phase or
become permanent
DNA Replication occur, Centriole double in animal Change 2n 25-33
S cell in cytoplasm, histone synthesis, Euchromatin from 2c to percent
replicate first 4c
Cell prepare for divisions; Tubulin protein synthesis 4c 2n 15
G2 occur percent
Time- Sequence – G1>S>G2>M (according to time) (human cell -24-hour, yeast cell -90 min
Quiescent stage (G0)- do not divide further exit G1 phase, metabolically active, no longer
proliferate or grow unless require by organism (cell is living)
- Some cells in the adult animals do not appear to exhibit division (e.g., heart cells and neuron)
M Phase-Actual cell division, mitosis occurs, 5%-time, M-phase - karyokinesis + cytokinesis, most
dramatic period, equational division- number of chromosomes in the parent and progeny cells is the same
Occur in – haploid cell (plants and some animals like egg to drone) Diploid cell (plants and animals)
