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Mitosis. Mitosis is the process by which new cells are generated. Mitosis produces 2 genetically identical daughter cells. Overview of Mitosis:. Parent cell. Replicated chromosomes condense at the start of mitosis. Mitosis. Sister chromatids separate and two daughter cells are formed.

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Mitosis l.jpg
Mitosis

  • Mitosis is the process by which new cells are generated.

  • Mitosis produces 2 genetically identical daughter cells


Overview of mitosis l.jpg
Overview of Mitosis:

Parent cell

Replicated chromosomescondense at the start of mitosis

Mitosis

Sister chromatids separate and two daughter cells are formed.

Parent cell and daughter cell contain thesame complement of chromosomes.



Figure 12 5 the stages of mitotic cell division in an animal cell g 2 phase prophase prometaphase l.jpg
Figure 12.5 The stages of mitotic cell division in an animal cell: G2 phase; prophase; prometaphase


Slide5 l.jpg
Figure 12.5 The stages of mitotic cell division in an animal cell: metaphase; anaphase; telophase and cytokinesis.


Figure 12 5x mitosis l.jpg
Figure 12.5x Mitosis animal cell: metaphase; anaphase; telophase and cytokinesis.


How do spindle fibers move the chromosomes l.jpg
How do spindle fibers move the chromosomes? animal cell: metaphase; anaphase; telophase and cytokinesis.



Motor molecules of the kintochore walk along the microtubule taking the chromosome with it l.jpg
Motor molecules of the kintochore walk along the microtubule, taking the chromosome with it

As the chromosomes move toward the poles, the microtubules are broken down at the kinetochore end


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ATP microtubule, taking the chromosome with it

ADP+Pi

Motor molecules "walk" along a microtubule track

Transport vesicle

ATP

ADP+Pi

Kinesin

Microtubule


After the nucleus divides cytokinesis divides the cytoplasm forming two separate cells l.jpg
After the nucleus divides, cytokinesis divides the cytoplasm, forming two separate cells


Slide12 l.jpg

Figure 8.9a cytoplasm, forming two separate cells

Cytokinesis in animals

Cleavage furrow


Mitosis in a plant cell l.jpg
Mitosis in a plant cell cytoplasm, forming two separate cells


Bacteria divide by binary fission l.jpg
Bacteria divide by binary fission cytoplasm, forming two separate cells


Bacteria divide by binary fission15 l.jpg
Bacteria divide by binary fission cytoplasm, forming two separate cells


Bacteria divide by binary fission16 l.jpg
Bacteria divide by binary fission cytoplasm, forming two separate cells


Unregulated cell division can lead to cancer l.jpg
Unregulated cell division can lead to cancer cytoplasm, forming two separate cells

  • Many factors interact with each other to determine whether a cell will undergo mitosis

  • Cell cycle checkpoints normally insure that DNA replication and mitosis occur only when conditions are favorable and the process is working correctly.


Slide18 l.jpg

Cell-Cycle Checkpoints cytoplasm, forming two separate cells

G2 checkpoint

Pass this checkpoint if:• cell size is adequate• chromosome replication is successfully completed

M

Mitosis

G2

Second gap

Metaphase checkpoint

Pass this checkpoint if:• all chromosomes are

attached to mitotic spindle

G1

First gap

G1 checkpoint

DNA synthesis

Pass this checkpoint if:• cell size is adequate• nutrient availability is sufficient• growth factors (signals from other cells) are present

S


Cell cycle proteins regulate whether a cell will proceed past a particular cell cycle checkpoint l.jpg
Cell cycle proteins regulate whether a cell will proceed past a particular cell cycle checkpoint

  • cyclin-  a protein whose amount varies cyclically

  • cdk- another cell division control protein - a cyclin dependent kinase; active only when bound to cyclin

  • MPF- mitotic promoting factor...  

    • MPF is a kinaseenzyme, ones that switches on/off target proteins by phosphorylating them..... 

    • [cyclin + cdk = MPF]...    favors Mitosis

    • leads to destruction of cyclin itself



Slide21 l.jpg
Growth factor proteins are signal molecules that trigger a signal-transduction pathway leading to cell division

Platelet-derived growth factor


Cell division is also dependent on environmental factors l.jpg
Cell division is also dependent on environmental factors signal-transduction pathway leading to cell division


Unregulated cell division can lead to cancer23 l.jpg
Unregulated cell division can lead to cancer signal-transduction pathway leading to cell division

  • Mutations in genes that encode cell cycle proteins can lead to unregulated growth, resulting in tumor formation and ultimately invasion of cancerous cells to other organs.


Cancer cells have escaped cell cycle controls and divide excessively l.jpg
Cancer cells have escaped cell cycle controls and signal-transduction pathway leading to cell divisiondivide excessively


Figure 12 17x1 breast cancer cell l.jpg
Figure 12-17x1 Breast cancer cell signal-transduction pathway leading to cell division




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