Cell cycle

        Cell cycle - the series of cellular reproductive events in which duplication of cell content and cell division occur in an orderly loop sequence.

The stages in a cell cycle are divided into four phases - Interphase (G1, S and G2 phases)
                                                                                                 - Mitotic phase (mitosis and cytokinesis)

1. G1 phase - Cell growth 

• Cell growth and metabolic rate of cell is high.
• Protein and new cytoplasmic organelles are synthesised.
• At this stage, chromosomes appear as chromatin.

2. S phase - DNA replication 

• Synthesis of DNA.
• DNA undergoes replication.
• Each duplicated chromosome consists of two identical sister chromatids which contain identical copies of the chromosome's DNA molocule.

3. G2 phase - Preparation for mitosis

• Proteins and enzymes are required for cell division.
• The cell accumulates energy and completes its final preparations for cell division.

4. M phase - Cell divison 

• Nuclear and cytoplasmic divisions take place.