Published on March 5, 2014
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 DIVISON • Some cells divide constantly: cells in the embryo, skin cells, gut lining cells, etc. Epithelial Cell 7 WEEK EMBRYO
WHY CELL DIVISION? 2 YEARS OLD 16 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 ) 21 YEARS OLD
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 Nuclear envelope disappears
Prophase • Centrioles migrate to opposite poles of the cell. • Asters and spindle fibers form.
STEP 2 : • 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. Metaphase
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.
CYTOKINESIS • 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.
CYTOKENSIS In plant cells, a Cell Plate forms and separates Daughter Cells.
ANIMAL ANIMAL • Centriole and aster present • Daughter cells separated by cleavage furrow VS PLANT MITOSIS PLANT >No visible centriole or aster >Daughter cells separated by cell plate
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-lessonpowerpoint-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_AUoA Q&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_enZA57 1&espv=210&es_sm=93&source=lnms&tbm=isch&sa=X&ei=VxEXU6qqC8O5hAeEuoD4 BA&sqi=2&ved=0CAcQ_AUoAQ&biw=1280&bih=880#q=DOG+MAN&tbm=isch
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