Presentation on cell division via mitosis with voice

These slides are designed by Solomon K. Lagat – Introduction to Biology Course Unit 4,. 1

CELL DIVISIONDiscussion Forum Unit 4

Mitosis: The Cell Cycle

by Solomon K. Lagat

These slides are designed by Solomon K. Lagat – Introduction to Biology Course ,Unit 4. 2

CELL DIVISION

I am Solomon Lagat from Kenya, East Africa. I work in the Kenyan Judiciary to support delivery of justice using ICT. I am also a qualified Special Education teacher and I love teaching. I believe a teacher should be knowledgeable and this is the reason as to why I took this course which is totally unrelated to Computer Science which I am currently pursuing. I am going to take you through Cell Division or Mitosis.Enjoy the presentation!


What is mitosis?

Mitosis is a process in which one cell divides into two identical daughter cells that have similar genetic material. Mitosis occurs mainly in somatic cells.

•Cell division occurs through a cycle consisting of phases.•These phases include prophase, prometaphase, metaphase, anaphase, telophase and cytokinesis.


Interphase and mitosis

Interphase is clearly not part of mitosis.•At this stage, the cell engages itself in metabolic activity that prepares the cell it for mitotic division.

•In this case, a cell gets the idea that it is time to divide. It has to prepare everything i.e. duplicate DNA and get centrioles in the right position.

After the interphase, the next phases which we are going to explore include prophase, prometaphase, metaphase, anaphase, telophase and cytokinesis.


Prophase Chromatin in the nucleus

begins to condense and the nucleolus disappears.

Centrioles begin moving to opposite ends of the cell.

Fibers extend from the centromeres.

Some fibers cross the cell to form the mitotic spindle.


Prometaphase This phase begins by

dessolution of the nuclear membrane.

Proteins attach themselves to the centromeres forming the kinetochores.

Microtubules then attach themselves at the kinetochores and the chromosomes begin moving.


Metaphase At this phase, all of the pieces

are aligning themselves for the big split.

The DNA lines up along a central axis and the centrioles send out specialized tubules that connect to the DNA.

The DNA (chromatin) has now condensed into chromosomes.

Two strands of a chromosome are connected at the center with something called a centromere.

The tubules actually connect to the centromere, not the DNA.


Anaphase The separation begins

where half of the chromosomes are pulled to one side of the cell and the other half go the other way.

When the movement of chromosomes to the other side of the cell is complete, marks the beginning of telophase.


Telophase This is the time when

the cell membrane closes in and splits the cell into two pieces.

We will have two separate cells each with half of the original DNA.


Cytokinesis Cytokinesis in animals

happens when a protein fiber ring (actin) which is situated around the center of the cell contracts and pinches the cell into two daughter cells, each with one nucleus.


Conclusion

Importance of mitosis: Mitosis is one of the important part of the growth

and development process in both animals and plants.

It also makes it possible for tissues to repair i.e. healing when we get hurt.

For this to happen, mitosis maintains the same genetic makeup in both daughter cells.

http://www.biology.arizona.edu/cell_bio/tutorials/cell_cycle/MitosisFlash.html


References Thomson, C. (2014). Introduction to Biology.

Course eBook. Retrieved from: http://my.uopeople.org/mod/book/tool/print/index.php?id=45613

University of Arizona, (2004). The Cell Cycle & Mitosis Tutorial, Mitosis. The Biology Project. Retrieved from: http://www.biology.arizona.edu/cell_bio/tutorials/cell_cycle/cells3.html

http://www.biology.arizona.edu/cell_bio/tutorials/cell_cycle/MitosisFlash.html

Presentation on cell division via mitosis with voice

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