Gr:10 CELLS DIVISION: MITOSISgifs.africa/wp-content/uploads/2020/06/Grade-10...mitosis. Replacement of damaged plant or animal tissue (regeneration) Some organisms use mitosis to replace

BY: M.SAIDI for help +27848331738

www.thundermoviz.com facebook: & youtube THUNDERMOVIES chanel

For Study videos https://youtu.be/yObTZzrr2xI?list=UUxiZFebGmeJYi4hYQWESE_g

Gr:10

CELLS DIVISION: MITOSIS

https://youtu.be/yObTZzrr2xI?list=UUxiZFebGmeJYi4hYQWESE_g


INTRODUCTION


THE CELL CYCLE is the series of events that takes place in a cell that results in DNA replication and cell division

There are two main stages in the cell cycle.

1. interphase during which the cell grows and replicates its DNA.

2. mitotic phase (M-Phase) during which the cell divides and transfers one copy of its DNA to two identical daughter cells

THE SEQUENCE OF EVENTS


Interphase: DNA in chromatin network duplicates.

DNA thickens and becomes visible.


MITOSIS Purpose and location of mitosis

Growth – multicellular organisms need cell division to grow

Repair – organisms constantly repair and renew themselves; worn out or dead cells are replaced through cell division.

Reproduction – single-celled organisms, such as bacteria and protists, also reproduce by cell division (binary fission and budding).


MITOSIS OCCURS In plants

apical meristem tissues behind the tip of the root or stem and in buds

lateral meristem tissues underneath bark.

In animals

bone marrow

skin basal layers. BY: M.SAIDI for help +27848331738

Chromosome structure:


(1) Chromatid,

(2) Short and

(3) Centromere,

(4) Long arms of chromosome.

PHASES OF MITOSIS NOTE:

Mitosis Results: a mature cell divides into two identical new cells.

karyokinesis – division of the nucleus

cytokinesis – division of the cytoplasm

PHASES INCLUDE 1. prophase

2. metaphase

3. anaphase

4. telophase

. cytokinesis


iPMATc.

1. PROPHASE the nuclear membrane and nucleolus disintegrates

A centrosome forms centrioles.

centrioles separate and move to opposite poles

The centrioles give rise to the spindle fibres which form between the poles.

Each chromosome is visible as two chromatids joined by a centromere


2. METAPHASE chromosomes line up on the equator of

the cell.

Each chromosome is attached to the spindle fibres by its centromere.


3. ANAPHASE Each chromosome separates into its sister

chromatids by the action of spindle fibres pulling each towards a spindle pole.

Each chromatid is pulled to opposite poles of the cell


4. TELOPHASE a nuclear membrane reforms around the

daughter chromosomes that have gathered at each of the poles.

The daughter chromosomes uncoil to form chromatin once again.

The nuclear membrane reforms.


CYTOKINESIS is the division of the cytoplasm

Its not a stage of mitosis but the process of the cytoplasm splitting into two.

In an animal cell the cell membrane constricts

In a plant cell a cross wall is formed by the cell plate dividing the cytoplasm in two.

There are now two genetically identical daughter cells which are identical to the parent cell and to each other.


DIFFERENCES BETWEEN MITOSIS IN ANIMAL CELL AND PLANT CELL

ANIMAL CELL PLANT CELL

occurs throughout the body occurs in the meristem eg tip of root

Cytokinesis occurs by cleavage in animal mitosis

Cytokinesis occurs through the formation of a cell plate in plant mitosis

Centrosomes / sindle form Centrosomes /sindle don’t form


Living Process Role of Mitosis

Development and growth

The number of cells increases by mitosis

enabling organisms to grow from a single

cell to a complex multicellular organism.

Cell replacement

Cells are constantly lost and replaced by

new ones in the body, for example in the

skin and in the gut, red blood cells live for

only four months, and are replaced by

mitosis.

Replacement of damaged plant or

animal tissue (regeneration)

Some organisms use mitosis to replace

body parts. For example starfish replace

lost arms by mitosis.

Asexual reproduction

Some organisms such as the hydra use

mitosis to produce genetically identical

offspring. The process is known as

budding. Mitosis is also the method by

which yeast cells multiply. BY: M.SAIDI for help +27848331738

ROLE OF MITOSIS

Reproduction in some simple organisms

Asexual reproduction uses mitosis.

Eg in ciliated organism


Undergoing cytokinesis

CANCER is uncontrolled cell division and growth (mitosis), causing a

tumour to develop.

KINDS OF CANCER CELLS Benign tumours are cancerous cells found at the original site

that do not move through the body. are non-cancerous.

Malignant tumours leave the original site and move throughout the body invading other organs and tissues


https://www.insidecancer.org/

TYPES OF CANCER Breast cancer

Lung cancer

Oesophageal cancer

Leukaemia (blood cancer)

Melanoma (skin cancer)

sarcomas – bone, cartilage and muscle


CAUSES OF CANCER Cancer is caused by different factors called

carcinogens.

Carcinogens are:

inherited susceptibility

radiation (sun, X-rays, radioactivity)

smoking

hormonal imbalances

processed foods

pollutants

pesticides

viruses. BY: M.SAIDI for help +27848331738

Beliefs and attitudes about cancer It is people's fault if they get cancer

Cancer is a death sentence

If someone in your family has cancer you might get it too

Cancer is contagious and you can catch it from others

A positive attitude can cure cancer

Only old people get cancer

Only females get breast cancer

Only pale people get skin cancer


Cancer treatment Medical biotechnology used in cancer treatment is:

Surgery – to cut it out with a scalpel or laser

Chemotherapy – chemical compounds kill the cancer cells

Radiotherapy – can use machines, radiation, injections of compounds and capsules.


Chemotherapy Radiotherapy

Traditional technology used in cancer treatment includes natural remedies like Cancer Bush tea and African wild potato tea.


Cancer Bush tea African wild potato tea



For Study videos https://youtu.be/yObTZzrr2xI?list=UUxiZFebGmeJYi4hYQWESE_g

END OF TERM 2

PLANT AND ANIMAL TISSUES

https://youtu.be/yObTZzrr2xI?list=UUxiZFebGmeJYi4hYQWESE_g



For Study videos

Documents

Gr:10 CELLS DIVISION: MITOSISgifs.africa/wp-content/uploads/2020/06/Grade-10...mitosis. Replacement of damaged plant or animal tissue (regeneration) Some organisms use mitosis to replace