CELL DIVISION-----------------------.ppt

Cell Division

1. CELL DIVISION
Mesenchymal precursor cells http://www.mesoblast.com/
© 2016 Paul Billiet ODWS

2. Cell division is a fundamental process
All cells come from pre-existing cells
It is necessary to replace worn out cells in
multicellular organisms
It is required for growth in multicellular organisms
An increase in size will require an increase in surface area
to volume ration
Cell division subdivides the cytoplasm into small units
(cells) surrounded by plasma membranes
It is necessary for production of differentiated cells in
multicellular organisms
© 2016 Paul Billiet ODWS

3. Cell division and reproduction
It is necessary for
reproduction in
unicellular or
multicellular
organisms
microbus
http://www.microscope-microscope.org
© 2016 Paul Billiet ODWS

4. Prokaryotes
Prokaryotes have
no nucleus
They have a single
circular chromosome
Prokaryotes simply
divide their cells in
two by binary
fission
http://instruct1.cit.cornell.edu/
© 2016 Paul Billiet ODWS

5. Eukaryotes
Eukaryotesmust divide their nucleus (and
other organelles such as mitochondria) in
preparation for cell division (mitosis or
meiosis)
Before the nucleus divides the genetic
material replicates(duplicates)
© 2016 Paul Billiet ODWS

6. Mitosis
(From the Greek mitosa thread)
Mitotic division results
in genetically identical
eukaryotic cells (a
clone)
Mitosis is the basis of
asexual
reproduction
http://science.tjc.edu/
© 2016 Paul Billiet ODWS

7. Meiosis
Meiosis results in a halving of the
chromosome number in preparation for
fertilisation
Meiosis shuffles genes in new combinations
Meiosis results in genetically different cells
Meiosis and fertilisation are the basis of
sexual reproduction
© 2016 Paul Billiet ODWS

8. COMPARING MITOSIS AND
MEIOSIS
© 2016 Paul Billiet ODWS

9. COMPARING MITOSIS AND
MEIOSIS
© 2016 Paul Billiet ODWS