Cell division Mitosis

By Claudia Nhacolo

CONTENTS

• WHAT IS MITOSIS• CHROMOSOME• CELL DIVISION• PHASES- MITOSIS• EXTERNAL RESOURCES(VIDEO)• REFERENCES

WHAT IS MITOSIS?

• Mitosis is a process of nuclear division in eukaryotic cells conventionally divided into five stages.

• Mitosis produces two genetically identical cells.

• Mitosis is produced in the somatic cells that now make up your body and is also the means by which your body continues to generate new cells to replace dead and damaged ones.

• Mitosis is referred to in the following stages: Prophase, Metaphase, Anaphase, and Telophase.

BEFORE WE BEGIN WE MUST KNOW WHAT A CHROMOSOME IS

• A chromosome is a structure of DNA, protein, and RNA found in cells.

• It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences.

• Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.

HUMANS have 46 chromosomes in their cell.

STRUCTURE OF CHROMOSOME

• Chromosome: An organized structure of DNA and protein that is found in cells.

Cell Division

All living cells come from other living cells. During mitosis, the nucleus of the cell divides, forming two nuclei with identical genetic information.

CELL DIVISON7 WEEK EMBRYO

Epithelial Cell

• Some cells divide constantly: cells in the embryo, skin cells, gut lining cells, etc.

WHY CELL DIVISION?

2 YEARS OLD 16 YEARS OLD

21 YEARS OLD

Growth involves increase in the size of organisms and increase in the number of cells. Cell division is the process through which this is achieved. The new cells arise from pre existing cells only through the process of cell division. Cell division is essential for growth.

• IT’S HOW WE GROW!( LOOKING AT MICHEAL JACKSON )

WHY CELL DIVISION?

• Mitosis is important to us because it facilitates growth It also helps in cell replacement as throughout our lifespan, a lot of our cells die and are replaced and this would not be possible without mitosis.

IT’S how we Heal , and

Replace cells.

• CELL DIVISION : IPMAT

INTERPHASE• Interphase is the phase of the cell cycle in

which the cell spends the majority of its time and performs the majority of its purposes including preparation for cell division.

• Although, before it received the name Interphase, its name was the Resting phase. Once scientists discovered that the cell was doing the opposite of resting, they immediately changed it.

• Then, in preparation for cell division, it increases in size and makes a copy of its DNA, which is made during the S phase. Interphase is also considered to be the 'living' phase of the cell, in which the cell obtains nutrients, grows, reads its DNA, and conducts other "normal" cell function.

STEP 1 :Prophase

• Chromosomes become very dense. • The nuclear envelope breaks

down

• The spindles form at opposite "poles" of the cell

Prophase

Prophase

Nuclear envelope disappears

• Centrioles migrate to opposite poles of the cell.

• Asters and spindle fibers form.

Prophase

STEP 2 : Metaphase

• The chromosomes line up at the equator of the cell (metaphase

plate), with the centrioles at opposite ends and the spindle fibers attached to

the centromeres.

M E T A P H A S E

STEP 3 : ANAPHASE

• The sister chromatids (paired chromosomes) separate and begin moving to opposite poles of the cell

• Spindle fibers not connected to chromatids lengthen and elongate the cell

• At the end of anaphase, a complete set of chromosomes has assembled at each pole of the cell.

STEP 4: TELOPHASE

• Two daughter nuclei form in the cell.

• Nuclear envelopes are formed from the fragments of the parent cell’s nuclear envelope and other portions of the endomembrane system.

• Nucleoli reappear.

• The chromosomes become less condensed. Mitosis is complete.

• The division of the cytoplasm is usually almost complete by late telophase, so the two daughter cells appear shortly after the end of mitosis.

• In animal cells, cytokinesis involves the formation of a cleavage furrow, which pinches the cell in two.

CYTOKINESIS

CYTOKENSIS

In plant cells, a Cell Plate forms and separates Daughter Cells.

ANIMAL VS PLANT MITOSIS

ANIMAL PLANT• Centriole and >No visible centriole or aster

aster present

• Daughter cells >Daughter cells separated by cell plate

separated

by cleavage furrow

Can you name the stages?

1

2

3

4

5

Can you name the stages?

1 Prophase

2

3

4

5

Can you name the stages?

1 Prophase

2 Metaphase

3

4

5

Can you name the stages?

1 Prophase

2 Metaphase

3 Anaphase

4

5

Can you name the stages?

1 Prophase

2 Metaphase

3 Anaphase

4 Telophase

5

Can you name the stages?

1 Prophase

2 Metaphase

3 Anaphase

4 Telophase

5 Cytokinesis

External Resources

Right click on the image and open the hyperlink to watch a video “Have fun”

• Any QUESTIONS ?

REFERENCES• SLIDESHARES

http://www.slideshare.net/MRKALEMBER/mitosis-30635784

http://www.slideshare.net/sciencepowerpointcom/mitosis-lesson-

powerpoint-cell-division-celluar-division-quiz-activities

http://www.slideshare.net/guest0a84f2f/cell-division-by-mitosis

GOOGLE IMAGES

https://www.google.co.za/search?q=MICHAEL+JACKSON+when+she+was+2+years+old&source=lnms&tbm=isch&sa=X&ei=BeQWU63oN9GshQfN_oCoDg&ved=0CAcQ_AUoAQ&biw=1280&bih=923#q=MICHAEL+JACKSON+when+HE+was+2+years+old&tbm=isch

https://www.google.co.za/search?q=structure+of+chromosomes&rlz=1C1CHNQ_enZA571&espv=210&es_sm=93&source=lnms&tbm=isch&sa=X&ei=VxEXU6qqC8O5hAeEuoD4BA&sqi=2&ved=0CAcQ_AUoAQ&biw=1280&bih=880#q=DOG+MAN&tbm=isch