CELL DIVISION

 

Page Topics

Life Cycle of Cell and Interphase,

Mitosis Whitefish Blastula: Prophase, Metaphase, Anaphase, Telophase, Cytokinesis and Daughter Cells, Complete Whitefish Mitosis Video

Mitosis Onion (Allium) Root Tip: Prophase, Metaphase, Anaphase, Telophase, Cytokinesis and Daughter Cells, Complete Allium Video

Links to Mitosis


LIFE CYCLE OF THE CELL and INTERPHASE

Typically, the life cycle of a cell begins when the cell is produced by cell division. Daughter cells produced by mitosis either maintain their ability to divide again or will permanently remain in interphase. Interphase is the stage in the life cycle of the cell when the cell is performing all its normal metabolic functions except division.  Interphase for cells that maintain their ability to undergo mitosis is divided into three stages, G1, S, and G2. Cells that lose their ability to divide are described as being in permanent interphase, G0.

In preparation for mitosis, the interphase cell begins preparations for division with the duplication of the chromosomes and the centrioles.  The following illustrations show the duplication of the chromosomes and the centrioles in a pre-mitotic animal cell.

 

WATCH VIDEO OF INTERPHASE CELLS (WHITEFISH)


MITOSIS - WHITEFISH BLASTULA

Mitosis is the process of cell division in which the nucleus divides to produce two nuclei with the same types and numbers of chromosomes. Typically, at the end of mitosis the process of cytokinesis (the division of the cytoplasm) results in the formation of two new daughter cells, each with one of the identical nuclei formed by mitosis.  Mitosis is a continuous event but for study mitosis is divided into the following sequential four stages: (1) prophase, (2) metaphase, (3) anaphase, and (4) telophase.

The following illustrations and videos present mitosis as seen in the slide preparations of the "Whitefish blastula."  The preparation is made from the embryonic stage called the blastula, the stage characterized by a spherical layer of cells surrounding a central fluid-filled cavity.  The blastula is sectioned and typically many of the sections are included on the preparation. Thus, microscopic observation for the stages of mitosis requires searching the sections for the cells that show the events that characterize each stage.


Prophase (whitefish)

Prophase is the first stage of mitosis and includes the following events: the nuclear membrane disappears, the nucleoli disappear, a pair of centrioles moves to form each pole and the mitotic spindle forms between the poles (centrioles), aster fibers extend from the poles (centrioles), and the replicated DNA begins to condense into distinctive chromosomes.

 

WATCH VIDEO OF PROPHASE CELLS (WHITEFISH)


Metaphase (whitefish)

Metaphase is the second stage of mitosis and is characterized by the alignment of the chromosomes along the equator of the cell.

 

WATCH VIDEO OF METAPHASE CELLS (WHITEFISH)


Anaphase (whitefish)

Anaphase is the third stage of mitosis and is characterized by the separation of the chromosomes and the movement of the each of the replicated chromosomes toward opposite poles.

 

WATCH VIDEO OF ANAPHASE CELLS (WHITEFISH)


Telophase (whitefish)

Telophase is the fourth (last) stage of mitosis and begins when the chromosomes stop their movement at the poles. Telophase is characterized by the dispersal of the chromosomes into chromatin, the nuclear membrane reforms, the nucleoli reappear, and the mitotic spindle and aster fibers disappear. Mitosis is complete with the formation of two nuclei, each with the same number and types of chromosomes.  The formation of a cleavage furrow, part of cytokinesis (division of the cytoplasm) is evident during telophase.

 

WATCH VIDEO OF TELOPHASE CELLS (WHITEFISH)


Cytokinesis and Daughter Cells (whitefish)

At the completion of mitosis, the cell usually divides into two cells, each with one of the newly formed nuclei. Cytokinesis is defined as the division of the cytoplasm and is characterized by the formation of the cleavage furrow. Usually, the cleavage furrow begins to form during anaphase and at the end of telophase its inward movement results in the division of the cell into the two daughter cells.

 

WATCH VIDEO OF DAUGHTER CELLS (WHITEFISH)


Whitefish Interphase and Mitosis

WATCH COMPLETE VIDEO OF WHITEFISH INTERPHASE AND MITOSIS



ONION ROOT TIP INTERPHASE

Interphase (Allium root tip)

 Interphase is the stage in the life cycle of the cell when the cell is performing all its normal metabolic functions except division. In preparation for mitosis, the interphase cell begins preparations for division with the duplication of the chromosomes and the centrioles. Observation of an interphase cell of the Allium root tip reveals a distinctive nucleus with dispersed DNA (chromatin) and nucleoli.

 

WATCH VIDEO OF INTERPHASE CELLS (Allium root tip)


MITOSIS - ONION (ALLIUM) ROOT TIP

Mitosis is the process of cell division in which the nucleus divides to produce two nuclei with the same types and numbers of chromosomes. Typically, at the end of mitosis the process of cytokinesis (the division of the cytoplasm) results in the formation of two new daughter cells, each with one of the identical nuclei formed by mitosis.  Mitosis is a continuous event but for study mitosis is divided into the following sequential four stages: (1) prophase, (2) metaphase, (3) anaphase, and (4) telophase.

The following illustrations and videos present mitosis as seen in the slide preparations of the "Onion (Allium) Root Tip."  The preparation is made from the growing tip of the root of the onion. The root tip is sectioned and typically several sections are included on the preparation. Thus, microscopic observation for the stages of mitosis requires searching the sections for the cells that show the events that characterize each stage.  Two of the major differences observed between observation of the cells of the whitefish and onion is that the onion has distinctive cell walls, and the poles (centrioles) and spindle apparatus are not usually seen.


Prophase (Allium root tip)

Prophase is the first stage of mitosis and includes the following events: the nuclear membrane disappears, the nucleoli disappear, a pair of centrioles moves to form each pole and the mitotic spindle forms between the poles (centrioles), aster fibers extend from the poles (centrioles), and the replicated DNA begins to condense into distinctive chromosomes. Observation of a prophase cell of the Allium root tip reveals a distinctive nucleus with darkly stained chromosomes and nucleoli.

 

WATCH VIDEO OF PROPHASE CELLS (Allium root tip)


Metaphase (Allium root tip)

Metaphase is the second stage of mitosis and is characterized by the alignment of the chromosomes along the equator of the cell.

 

WATCH VIDEO OF METAPHASE CELLS (Allium root tip)


Anaphase (Allium root tip)

Anaphase is the third stage of mitosis and is characterized by the separation of the chromosomes and the movement of the each of the replicated chromosomes toward opposite poles.

 

WATCH VIDEO OF ANAPHASE CELLS (Allium root tip)


Telophase (Allium root tip)

Telophase is the fourth (last) stage of mitosis and begins when the chromosomes stop their movement at the poles. Telophase is characterized by the dispersal of the chromosomes into chromatin, the nuclear membrane reforms, the nucleoli reappear, and the mitotic spindle and aster fibers disappear. Mitosis is complete with the formation of two nuclei, each with the same number and types of chromosomes.  The formation of a cell plate (new wall), part of cytokinesis (division of the cytoplasm) is evident during telophase.

WATCH VIDEO OF TELOPHASE CELLS (Allium root tip)


Cytokinesis and Daughter Cells (Allium root tip)

At the completion of mitosis, the cell is divided into two cells, each with one of the newly formed nuclei, by the formation of a cell wall between the cells.  Cytokinesis is defined as the division of the cytoplasm and in plant cells is characterized by the formation of a new wall between the daughter cells.

 

WATCH VIDEO OF DAUGHTER CELLS (Allium root tip)


Allium Video of Interphase and Mitosis

WATCH COMPLETE VIDEO OF ALLIUM INTERPHASE AND MITOSIS



LINKS to MITOSIS VIDEOS

Mitosis World (Salmon Lab)

North Harris College Biology Department

Cells Alive (cellsalive.com)

Iknow.net

Hybrid Medical Animation

  • Promotional Animation of Stages of Mitosis
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    This site was last updated 06/30/07