Cell division and growth occur through the cell cycle, which consists of interphase and the mitotic phase. During interphase, the cell grows and duplicates its DNA in preparation for division. Interphase includes G1, S, and G2 phases where the cell accumulates building blocks and energy for DNA replication in S phase. In mitosis, the duplicated DNA and cell contents are separated into two daughter cells through karyokinesis and cytokinesis. Cell division allows organisms to grow, develop, replace old cells, and produce new cells or organisms.

1. Cell division and cell growth

2. Cell division
• All cells are produced by divisions of pre-
existing cell.
• Continuity of life depends on cell division
• Cell division is the process by which a
parent cell divides into two or more
daughter cells.
• Because of the cell division, organisms grow
and develop, replace old or damaged cells,
and produce new cells or organism.

3. Cell cycle
• The cell cycle or cell-division cycle is the series
of events that take place in a cell leading to its
division and duplication of its DNA (DNA
replication) to produce two daughter cell
• The cell cycle is an ordered series of events
involving cell growth and cell division that
produces two new daughter cells

5. • The cell cycle is the period from the
beginning of one division to the
beginning of the next
• the cell cycle has two major phases:
interphase and the mitotic phase
• During interphase, the cell grows and DNA is
replicated.
• During the mitotic phase, the replicated DNA
and cytoplasmic contents are separated, and
the cell divides.

6. Interphase
• Interphase is the first stage of the cell cycle
• During interphase, cells grow, make copies of
their DNA, and prepare to divide into two new
cells
• Cell prepare itself so that it can be divided into
daughter cells
• It is divided into three phases
• G1
• S
• G2

7. G1
• The first stage of interphase is called the G1 phase (first
gap)
• Cell active biochemically
• it either occupies 30 to 50 per cent
• The cell is accumulating the building blocks of
chromosomal DNA
• associated proteins as well as accumulating sufficient
energy reserves to complete the task of replicating each
chromosome in the nucleus.
• since it involves synthesis of RNA, proteins i.e DNA
polymerase and membranes which leads to the growth of
nucleus and cytoplasm of each daughter cell
• ENZYMES

8. S Phase (Synthesis of DNA)
• Throughout interphase, nuclear DNA remains
in a semi-condensed chromatin configuration
• DNA gets doubled
• Centrosome divide give rise to centriole
• Start moving opposite pole
• each chromosome has two DNA molecules
and a duplicate set of genes
• 35 to 45 per cent of cell cycle

9. G 2
• Some cell organelles are duplicated
• Cells make copies of their mitochondria and
chloroplasts
• REMAING PROTEIN LIKE MICROTUBLES,
MITOSIS SPECIFIC PROTEINS
• At the end of Interphase, the cell is ready to
divide

10. M phase
• It is phase of division
• After the early preparatory period now cells
ready to divide and divide by many ways
• It is again of two types
• Mitosis
• Meiosis
• Amitosis (occur in lower organism only
without inter phase)

11. TWO DIVISION
• KARYOKINESIS
• CYTOKINESIS

12. Amitosis
• Occur in those organism which lack nucleus
and membrane bound organelle.
• It is type of A sexual reproduction
• Cells divide directly without spindle formation
and without appearance of chromosome
• The polyploid macronucleus found
in Ciliates divides mitotically
• BINARY FISSION AND