Cell Division: Concept Map

Cell division: Concept map
CELL DIVISION
Comprises of
Mitosis Meiosis
Subdivides into
Controlled mitosis Uncontrolled mitosis

Meiosis I Meiosis II
Lead to Lead to
Cloning
(asexual reproduction,
Cause by Testis, ovary
regeneration, healing)
Advantages and
disadvantages of cloning
Objectives:
• Describe about the necessity for the production of new cells in
organisms
• Stote the significance of mitosis
• Identify the phases in the cell cycle
• Explain the process of mitosis, meiosis and cytokinesis
Mitosis
• Mitosis is a division of the nucleus to produce two new
daughter cells containing chromosomes identical to the
parent cell.
Significance of mitosis
• Growth-allows a zygote to produce more cell in-order to

grow
• Repair and replacement- allow the multicellular organism
maintain its tissues, example skin cells and blood
• Asexual reproduction- clone
Phases in the cell cycle
• The cell cycle divided into two major phases

a. Interphase
b. Mitosis
• Interphase is the period between
division, divided into 3 sub phases (G1, S and G2)
 G1- cells grow rapidly and new organelle are
synthesis
 S- synthesis of DNA and chromosomes are
replicated
 G2- cells prepares for mitosis, synthesis protein and
mitotic spindle begin to form
Mitosis
• Mitosis is a continuous process and divided
into 4 main phases based on the appearance
and behavior of the chromosomes.
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
Prophase
Early prophase
• Chomatids condense and become visible
in a light microscope
• Nucleolus disappears
• Paired centrioles move to opposite ends of
the cell
Late prophase
• Nuclear membrane disappears
• Spindle form
Metaphase
• Spindle fibres are fully form
• Sister cromatids line up at the spindle equator
• At the end of metaphase, the centromeres divide
Anaphase
• Anaphase begin with the separation of the

centromers
• The sister cromatids are drawn to opposite poles
of the cell by contraction of spindle fibres
Telophase
• Telophase begin when the two sets of daughter
chromosomes have reached the two poles of the
cell.
• The spindle fibres disintegrate, the nuclear

membrane forms around each set of daughter
chromosomes and the nucleoli reappear.
• The chromosomes uncoil and become less visible

under the light microscope.
Meiosis
• In a diploid cell, chromosomes occur as pairs
(homologous chromosomes).
• Meiosis is a process to convert a diploid cell to a

haploid gamete and cause a change in the genetic.
information to increase diversity in the offspring.
• Meiosis involves two successive nuclear division

that produce four haploid cells. The first division
(meiosis I) is the reduction division; the second
division (meiosis II) separates the chromatids.
The effects of uncontrolled mitosis in
living things
• Mutation is the change in the DNA structure of
the cell.
• This change in the DNA corrupts the coded

genetic instructions for mitosis control.
• This leads to uncontrolled mitosis, which is the

non-stop division of cells, producing a mass of
new daughter cells, called tumour.
Causes of Cancer
1. Genetic- some forms of cancer like
prostate, colon, breast, skin, ovary are suspected to be
inherited from the parents
2. Carcinogens- these are chemicals which affect

genetic activity and cause cancer, e.g. of carcinogen
a diesel exhaust, cigarette smoke, hair
dyes, soot, arsenic, benzene and formaldehyde.
3. Radiation- excess exposure to x-ray, gamma-rays and

ultra violet rays lead to increase cancer risk.
4. Age- some cancers are found primarily in young

people (e.g. leukemia), while some cancers (e.g.
colon cancers) are found mostly in older adults.
5. Viruses- some viruses (such as the EB and HIV-1)

cause cancer.
Cloning
1. Cloning is the process of the making Clones are
genetically identical cells produced from a single
parent cell by mitotic division, or through asexual
reproduction.
2. Genetically identical copies of an original plant
or animal.
3. We shall study the application of knowledge on
mitosis the cloning of
a) Microbes
b) Plants
c) animals
Cloning of Microbes
• Clone microbes using cells culture and
fermenters
• Cell culture
a) You can easily clone microbes
(bacteria and some
fungi) in you science laboratory through natural
asexual reproduction.
b) First, grow a sample of microbial cells on a solid
nutrient medium in an agar plate.
c) Then identify, isolate and select strain from the
agar plate and grow it in liquid medium in a
culture flask.
• Fermenters
a) Fermenters are vessels use in biotechnology
to grow microbes on a large scale.
b) Microbes, like yeast are mixed with a culture
medium and left in a fermenters to grow by
mitosis.
c) The fermenters is constantly stirred, and
aerated.
d) The environmental conditions ( such as
pH, oxygen, pressured and temperature) are
constantly monitored using proves ti ensure
the maximum growth of the microbes.
Cloning of animals
• There are two types of animal cloning
according to purpose:
1. Reproductive cloning
Producing an entire animal that is genetically identical
to the parent animal
The entire animal is produced from a single cell by
asexual reproduction through mitosis.
2. Therapeutic cloning
Is a branch of medicine concerned with the
treatment of diseases.
Parts of a person skin, heart, liver or even just a few
cells are duplicated to produce a clone.
The clone tissue is used to replace a damaged
or diseases tissue without the risk of tissue rejection.

Cell Division: Concept Map

Uploaded by

Copyright:

Available Formats

Cell Division: Concept Map

Uploaded by

Document Information

Original Title

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

Cell Division: Concept Map

Uploaded by

Copyright:

Available Formats

Cell division: Concept map

Controlled mitosis Uncontrolled mitosis

• Growth-allows a zygote to produce more cell in-order to

• The cell cycle divided into two major phases

• Anaphase begin with the separation of the

• The spindle fibres disintegrate, the nuclear

• The chromosomes uncoil and become less visible

• Meiosis is a process to convert a diploid cell to a

• Meiosis involves two successive nuclear division

• This change in the DNA corrupts the coded

• This leads to uncontrolled mitosis, which is the

2. Carcinogens- these are chemicals which affect

3. Radiation- excess exposure to x-ray, gamma-rays and

4. Age- some cancers are found primarily in young

5. Viruses- some viruses (such as the EB and HIV-1)

You might also like