The document discusses cell division, emphasizing mitosis and meiosis as critical processes in cellular reproduction. Mitosis results in two daughter cells with identical genetic information, while meiosis produces gametes with half the chromosome number for sexual reproduction. Key stages of the cell cycle, including interphase, prophase, metaphase, anaphase, telophase, and cytokinesis, are outlined, illustrating the complexities of these cellular processes.

1. By Prof. Liwayway Memije-Cruz
Cell Division

2. Reproduction and
Cell Division
 means producing offspring that
may or may not be exact copies
of their parents.
 a part of a life cycle, which is a
series of events wherein
individuals grow, develop, and
reproduce according to a
program of instructions
encoded in DNA, which they
inherit from their parents.
When cells divide, each
daughter cell receives a
complete copy of DNA and
enough cytoplasmic machinery
to start up its own operation.
DNA contains the blueprints for
making different proteins.
Some of the proteins serve as
structural materials. Others
serve as enzymes for reactions
by which carbohydrates, lipids
and other substances are
formed.

3. Cell Division

5. Cell Cycle

6. Cell Cycle

7. Mitosis
 Mitosis is a division of cell nucleus,
which results in the formation of
two daughter nuclei with exactly
the same genes as the mother
nucleus. When the nucleus
divides, each daughter cell ends up
with exactly the same genetic
information as the original mother
and the original fertilized egg from
which it came. The life cycle of a
cell extends from the time that the
cell is formed until its division has
been completed.
 Mitosis is only a small part of the
cycle; it lasts only for a few
minutes or an hour or more.
Typically, it takes for 2 hours.
 Mitosis provides the new cells for
body growth in youth and vital to
repair body tissues all through life.
 The cycle has two major periods:
interphase and cell division.

8. Prophase
The chromosomes are seen to consist of two chromatids joined by a
centromere. The centrioles move apart toward opposite poles of the cell.
Spindle fibers are produced and extend from each centrosome. The
nuclear membrane starts to disappear and the nucleolus is no longer
visible.

9. Metaphase
The chromosomes are
lined up at the equator
of the cell. The spindle
fibers from each
centriole are attached
to the centromeres of
the chromosomes and
the nuclear membrane
has disappeared.

10. During anaphase,
sister chromatids of
each chromosomes
are separated.
Microtubule-based
mechanisms move the
two chromatids of
each pair to opposite
poles. Anaphase

11. Telophase
Telophase is essentially
prophase in reverse.
Microfilaments begin
to constrict at
equatorial plane. New
nuclear membranes
start forming. The
nucleus reappears. Cell
division is nearly
complete.

12. Anaphase
Prophase
Telophase
Metaphase

13. Cytokinesis is the cytoplasmic
division accompanying or
following nuclear divisions. The
onset of cytokines is marked by the
appearance of scattered deposits of
materials around microtubules at the
spindle equator. The deposits then
accumulate until they form a distinct
layer across the cell. Then there
is the appearance of a shallow
ring-like depression at the plasma
membrane called cleavage furrow.
At the cleavage furrow, a ring of
contractile microfilaments attached
to the plasma membrane pulls
the membrane inward eventually
dividing the cytoplasm into two.
Thus at the end of cell division, two
identical daughter cells exist.
Cytokinesis or
cytoplasmic division

15.  Meiosis is used for just one purpose in the human body:
the production of gametes—sex cells, or sperm and eggs.
Its goal is to make daughter cells with exactly half as
many chromosomes as the starting cell.
 Meiosis in humans is a division process that takes us
from a diploid cell—one with two sets of
chromosomes—to haploid cells—ones with a single set
of chromosomes. In humans, the haploid cells made in
meiosis are sperm and eggs. When a sperm and an egg
join in fertilization, the two haploid sets of chromosomes
form a complete diploid set: a new genome.
Meiosis

16. References
 http://pediaa.com/difference-between-interphase-and-prophase/
 https://biologyaipmt.com/2016/06/06/chapter-10-cell-cycle-and-
cell-division/
 https://www.nature.com/scitable/definition/cytokinesis-100
 https://www.khanacademy.org/science/biology/cellular-molecular-
biology/mitosis/a/phases-of-mitosis
 https://www.khanacademy.org/science/biology/cellular-molecular-
biology/meiosis/a/phases-of-meiosis