1. Mitosis
CELL DIVISION FOR
GROWTH OF
EUKARYOTIC
ORGANISMS AND
REPLACEMENT OF
SOME EUKARYOTIC
CELLS
Presented By:
⢠Tashfeen Ahmad
Group :GM4-19
Presented to:
Dr. Ayesha Zaman
2. What is Mitosis?
⢠Mitosis is cell division which begins in
the fertilized egg (or zygote) stage and
continues during the life of the organism
in one way or another. Each diploid (2n)
daughter cell is genetically identical to the
diploid (2n) parent cell.
3. Walther Flemming (1843 â 1905)
⢠Described the process of cell division in 1882
and coined the word âmitosisâ
⢠â˘Also responsible for the word âchromosomeâ
which he first referred to as stained strands
⢠â˘Co-worker Eduard Strasburger named the
mitotic stages âprophase, metaphase,
anaphase, telophaseâ in 1884
4. What is Mitosis?
Walther Flemmingâs
book:
Zellsubstans, Kern
und Zelltheilung
(Cell-Substance,
Nucleus, and Cell-
Division)
Illustration showing
chromosomes and the
process of mitosis, 1882
6. Why Do Cells Undergo Mitosis?
⢠Mitosis is exact nuclear division. The DNA in the parent cell is
copied exactly and then the cell nucleus divides exactly so
each of the two daughter cells has the same kind and number
of genetic base pairs arranged in chromosomes as the parent
cell.
⢠ďMitosis is necessary because when cells reach a surface area
to volume ratio that is too small relative to the rate of
diffusion of nutrients and water into the cell, and thus the
nutritional demands of the cell cannot be met.
⢠ďIn order to address this, the cell undergoes mitosis to form
two identical, but smaller cells, which increases the surface
area to volume ratio, and thus the rate of diffusion can meet
the nutritional demands of the entire cell.
7. Interphase
⢠The cell prepares for division
⢠Animal & Plant Cell
â DNA replicated (copied)
â Makes new organelles (synthesis)
â Cell increases in size (growth)
12. Metaphase
⢠The cell prepares chromosomes for division
⢠Animal & Plant Cell
â Chromosomes line up at the middle of the cell
â Spindle fibers attach to chromosomes at the
centromere
â SHORTEST phase of mitosis
14. Anaphase
⢠The chromosomes divide
⢠Animal & Plant Cell
â Spindle fibers pull chromosomes apart
â ½ of each chromosome (called chromatid) moves
to poles of cells
15. Telophase
⢠The cytoplasm divides
⢠Animal Cell
â DNA uncoils & appears as chromatin again
â 2 nuclei form
â Cell membrane pinches in to form the 2 new daughter cells
⢠Plant Cell
â DNA uncoils & appears as chromatin again
â 2 nuclei form
â New cell wall forms between two nuclei to form the 2 new
daughter cells