BIOLOGY BY – GARIMMA MAM
CELL CYCLE AND DIVISION
1.Growth and reproduction are the two main characteristic of cells.
2.All the cells divide into two with each parent cell giving rise to two daughter cells.
3.Cell division is a very important process in the life of all living organisms.
4.Cell division, DNA replication and cell growth take place in a coordinated manner to ensure
correct division and formation of progeny/daughter cells with intact genome ( properly
distributed genetic material ).
Cell division – the sequence of events in which a –
1. Cell duplicates its genome ( genetic material )
2. Synthesis other constituents of cell ( like proteins , enzymes etc )
3. And eventually divides into two daughter cells.
Cell growth is a continuous process where as DNA replication takes place only once that is
during a particular stage in the process of cell cycle.
All the events of the cell cycle are under genetic control.
Karyokinesis – nuclear division
, PHASES OF CELL CYCLE
INTERPHASE / RESTING M PHASE / MITOTIC
PHASE / PREPARATORY PHASE / MITOSIS
PHASE
INTERPHASE –
The interphase though called the resting phase , is a metabolically active stage. It is the stage
where cell prepares itself for cell division by undergoing cell growth and forming and
collecting all the essential constituents of the cell. This phase is further divided into 3 parts –
1. G- 1 phase ( Gap 1 ) – it is the interval between mitosis and initiation of DNA replication.
The cell here is metabolically active and continues to divide and grow but does not
replicates its DNA. Most organelles divide at this stage.
2. S phase ( synthesis ) – as the name , here in this stage DNA synthesis and replication takes
place. During this stage the amount of DNA in a cell doubles whereas the number of
chromosomes remains the same. So if the cell has 2C amount of DNA and 2n amount of
chromosomes at G1 phase , after the S phase the amount of DNA will be 4C and the
number of chromosomes will be 2n .
CELL CYCLE AND DIVISION
1.Growth and reproduction are the two main characteristic of cells.
2.All the cells divide into two with each parent cell giving rise to two daughter cells.
3.Cell division is a very important process in the life of all living organisms.
4.Cell division, DNA replication and cell growth take place in a coordinated manner to ensure
correct division and formation of progeny/daughter cells with intact genome ( properly
distributed genetic material ).
Cell division – the sequence of events in which a –
1. Cell duplicates its genome ( genetic material )
2. Synthesis other constituents of cell ( like proteins , enzymes etc )
3. And eventually divides into two daughter cells.
Cell growth is a continuous process where as DNA replication takes place only once that is
during a particular stage in the process of cell cycle.
All the events of the cell cycle are under genetic control.
Karyokinesis – nuclear division
, PHASES OF CELL CYCLE
INTERPHASE / RESTING M PHASE / MITOTIC
PHASE / PREPARATORY PHASE / MITOSIS
PHASE
INTERPHASE –
The interphase though called the resting phase , is a metabolically active stage. It is the stage
where cell prepares itself for cell division by undergoing cell growth and forming and
collecting all the essential constituents of the cell. This phase is further divided into 3 parts –
1. G- 1 phase ( Gap 1 ) – it is the interval between mitosis and initiation of DNA replication.
The cell here is metabolically active and continues to divide and grow but does not
replicates its DNA. Most organelles divide at this stage.
2. S phase ( synthesis ) – as the name , here in this stage DNA synthesis and replication takes
place. During this stage the amount of DNA in a cell doubles whereas the number of
chromosomes remains the same. So if the cell has 2C amount of DNA and 2n amount of
chromosomes at G1 phase , after the S phase the amount of DNA will be 4C and the
number of chromosomes will be 2n .
