This document summarizes the process of cell division through mitosis and its key stages. It defines key terms like chromosomes, chromatids, and interphase. It describes the main stages of mitosis - prophase, metaphase, anaphase, and telophase. It explains that during cell division, the genetic material (DNA) is distributed into two identical daughter cells. The goal of cell division is reproduction of cells for growth, repair, and replacement of dead cells.

1. Edited by: Hasimah Azit

2. CELL DI VI SI ON
FUNCTI ONS I S t o :
Produce new cells for:
reproduction – gamete
growth – new cells
and repair – replace dead
cells

3. Basi c def i ni t i ons
 gene - basic unit of heredity; codes for a specific
trait
 somatic cell - all body cells except reproductive
cells
 gamete - reproductive cells (i.e. sperm & eggs)
 chromosome - elongate cellular structure
composed of DNA and protein

4. Basic definitions
 diploid (2n) - cellular condition where each
chromosome type is represented by two
homologous chromosomes
 haploid (n) - cellular condition where each
chromosome type is represented by only one
chromosome
 chromatid - one of two duplicated chromosomes
connected at the centromere
 centromere - region of chromosome where
microtubules attach during mitosis and meiosis

5. Ce l l di vi s i on i nvol ve s
 the distribution of identical genetic material,
DNA
 to two daughter’s cells.
2n
two
identical
daughter
2n cells
2n

6. The Cell Cycle

7. Ce l l Cyc l e
 The dividing and non-dividing stages in the life of a
cell.
 Phases:
1. Interphase: growth and DNA replication
Interphase
2. Prophase
3. Metaphase
4. Anaphase
Mitotic division
5. Telophase
6. Cytokinesis – cytoplasm divided

8. I nt e r phas e
1. G1 (gap) phase:
a. grow into matured size and protein is synthesized
b. most cell are arrested in this phase.
phase
2. S phase:
a. DNA replication takes place.
3. G2 (gap) phase:
a. Cellular growth and energy and organelles
preparation for M phase.
phase

9. M t os i s
i
The form of cell division by which a somatic
cell duplicates.
Mitosis is asexual reproduction.
Cell division is the continuation of life based
on the reproduction of cells.

10. Mitosis division
mitosis - nuclear/chemical events resulting
in two daughter nuclei which
have identical genetic material to
each other and to the mother cell
cytokinesis - division of the cytoplasm.

11. Look at the section through the tip of
an onion root tip and try to recognize:
* dividing cells – mitotic cells
* elongated cells

12. Onion root tip
Elongated cells Mitotic cells

14. I nt e r phas e
Nucleus and nucleolus visible.
chromatin Nuclear
membrane
cell membrane
nucleolus

15.  A chromosome is made up
of a DNA
 Chromatin is a long, thin
fiber that is folded and
coiled (invisible).
chromosome

16. Duplication of chromosome – from single strand to double strand

18. Chr om om r e pl i c at i on
os e
 A replicated chromosome consist of two strands
of identical chromosomal material called
chromatids (sister chromatids).
chromatids
chromosome
S phase: chromosomes replicate
chromatid
chromosome
chromatid
centromere

19. Chromatid
 A chromatid is a chromatid as long as it is held in
association with a sister chromatid at the
centromere.
centromere
centromere
chromatid
chromosome
chromatid

20. Pr ophas e
 Longest phase
 Nucleolus disappears
 Chromatin material condenses into chromosomes,
chromosomes
consisting of two sister chromatids.
chromatids

21. Pr ophas e
 Centrioles move apart (not found in plants).
 Spindle fibers form and attach from centrioles to
centromeres
 Nuclear envelope fragments and disappears.

22. Pr ophas e
early prophase late prophase
centrioles
spindle fibers
aster
fibers
nuclear envelope
disappearing
centromere

23. Find the stages in the picture below

24. M t aphas e
e
 Shortest phase
 Centrioles are at opposite ends of the cell and
attached with aster fibers.
fibers
 Chromosomes move to the metaphase plate
(equatorial plate - center of cell).

25. M t aphas e
e
centrioles
aster
fibers
spindle fibers
metaphase plate

26. Anaphas e
 Centromeres uncouple and spindle fibers
shorten.
 Sister chromatids separate and move apart.
 After separation, chromatids are now considered
chromosomes.
chromosomes

27. Anaphas e
During this phase, the cell contains twice the
normal number of chromosomes.
chromosomes
Cell begins to elongate.
elongate
At the end, there are equal numbers of
chromosomes at the poles.

28. Anaphas e
No longer sister chromatids, now chromosomes
chromatids
aster
fibers
spindle fibers centrioles

29. Te l ophas e
 Cleavage furrow develops in animal cells
(Cytokinesis begins).
 Cell plate develops in plants (no cleavage
furrows in plants).
 Nucleolus reappears.
cell plate

30. Te l ophas e
 Nuclear membrane reappears.
 Chromosomes uncoil.
 In the end, two genetically identical nuclei
(karyokinesis completed) are present.

31. Te l ophas e
cleavage furrow (cytokinesis)
nuclear membrane reforming nucleolus reappears

32. Cyt oki ne s i s
 Cytoplasmic division
 Cell plate complete in plants
 In the end, two separate daughter cells produced
with single nucleus.
cell plate

33. Que s t i on :
 A cell containing 20 chromosomes at the
beginning of mitosis would, at its completion,
produce cells containing how many
chromosomes each?
each

34. Ans we r :
20 chromosomes

35. Que s t i on :
 A cell containing 40 chromatids at the beginning of
mitosis would, at its completion, produce cells
containing how many chromosomes each? each

36. Ans we r :
20 chromosomes

37. What i s cancer ?
 A cancer cell is a cell that grows out of
control.
 Unlike normal cells, cancer cells ignore
signals to stop dividing, to specialize, or to die
and be shed.
 Growing in an uncontrollable manner and
unable to recognize its own natural boundary,
the cancer cells may spread to areas of the
body where they do not belong.

38. White blood
cells
attack the
cancerous
cell!

39. Fi nd your sel f :
 How the cancerous cells look
like?
 How these cells affect the
health?
 How these cells spread?
 What causes the cancer in
human?

40. Websi t e f or you t o vi si t:
 http://www.cellsalive.com/mitosis.htm
 http://www.biology.arizona.edu/Cell_bio/tutorials
 http://www.accessexcellence.org/RC/VL/GG/mito

http://training.seer.cancer.gov/module_cancer_di