Introduction
Cell cycle - refers to sequence of events tha the cell undergo such as interphase, cell division, cell growth and development, aging and death.
Stages of the cell cycle:
1. Interphase
- metabolic stage
- no sign of cell division
- not a resting stage because the cell prepares itself for cell division
- chromatin appears isolated granules to form chromonemata which are chromosomes in their maximum length and minimum thickness.
3 phases:
G1 ( Gap 1 ) or first growth phase - enzymes and raw materials are made ready for DNA replication.
S phase or synthesis phase - stage of DNA replication.
G2 ( Gap 2 ) or second growth phase - protein needed for aster and spindle formation are synthesized.
2. Cell Division
Kinds of Cell division
a. mitosis - happen in the body cells. It is a diploid cell.
effects are: growth, repair of damaged tissues and replace dead cells
b. meiosis - happen in the sex cells such as sperm and egg
It makes number of chromosomes be halved. Human 46 chromosomes becomes 23. It is a haploid cell.