jueves, 12 de marzo de 2009

Diference between an animal cell and a plant cell...



An amimal cell has: Cell Membrane, cytoplasm, nucleus, Endoplasmic Reticulum, Ribosomes, Golgi Bodies, Mitochondria, Vacuoles, Cell Wall and Chloroplasts...
A plant cell has: Everything except Cell wall and Chloroplasts...
That is the diffrence between the plant cell and the animal cell..!

jueves, 19 de febrero de 2009

Meiosis...



Meiosis: A process of reductional division. When meiosis begins, the DNA in the original cell is replicated. It occurs in all eukaryotes.
Meiosis 1: is the same as mitosis.
Meiosis 2:
Prophase II: We see the disappearance of the nucleoli and the nuclear envelope again as well as the shortening and thickening of the chromatids.
Metaphase II: centromeres contain two kinetochores that attach to spindle fibers from the centrosomes (centrioles) at each pole.
Anaphase II: where the centromeres are cleaved.
Telophase II: uncoiling and lengthening of the chromosomes and the disappearance of the spindle.
That is when an organism forms...!

http://en.wikipedia.org/wiki/Meiosis
http://www.biology.iupui.edu/biocourses/n100/images/meiosis2cropped.jpg






jueves, 29 de enero de 2009

Cells...Mitosis

A cell is the smallest living organism and it is often called the building block of life.

Cells divide by mitosis.



Mitosis is a process which results in the production of two daughter cells from a single parent. The daughter cells are identical to one another and to the original parent cell.

Interphase: The cells cromosomes duplicate and the nuclkeus is clearly visible.

Prophase: Each chromosome has duplicated and now consists of two sister chromatics. The nuclear envelope breacks down into vesicles.


Metaphase: The chromosomes align at the equitorial plate and are held in place by microtubles attached to the mitotic spindle and to part of the centromere.


Anaphase: The chromosomes have separated.


Telephase: The cytoplasm is begining to separate.