Vocab

cell division-

The process by which a cell divides into two or more cells. Among prokaryotes, cell division occurs by simple fission. Among eukaryotes, the cell nucleus divides first, and then a new cell membrane is formed between the nuclei to form the new cell. Cell division is used as a means of reproduction in organisms that reproduce asexually, as by fission or spore formation, and sexually reproducing organisms form gametes through cell division. Cell division is also the source of tissue growth and repair in multicellular organisms. The two types of cell division in eukaryotic organisms are mitosis and meiosis.

3 types:

Binary Fission

Mitosis

Meiosis

chromatid-

Either of the two daughter strands of a duplicated chromosome that are joined by a single centromere and separate during cell division to become individual chromosomes.

centromere-

a specialized structure on the chromosome, appearing during cell division as the constricted central region where the two chromatids are held together and form an X shape.
interphase- he stage in the development of a cell following mitosis or meiosis, during which the nucleus is not dividing. In cells that will undergo further division, the DNA in the nucleus is duplicated in preparation for the next division.

cell cycle- the cycle of growth and asexual reproduction of a cell, consisting of interphase followed in actively dividing cells by prophase, metaphase, anaphase, and telophase.

mitosis-The process in cell division in eukaryotes in which the nucleus divides to produce two ne

w nuclei, each having the same number and type of chromosomes as the original. Prior to mitosis, each chromosome is replicated to form two identical strands (called chromatids). As mitosis begins, the chromosomes line up along the center of the cell by attaching to the fibers of the cell spindle The pairs of chromatids then separate, each strand of a pair moving to an o pposite end of the cell. When a new membrane forms around each of the two groups of chromosomes, division of the nucleus is complete. The four main phases of mitosis are prophase, metaphase, anaphase, and telophase. Compare meiosis.



prophase-the first stage of mitosis or meiosis in eukaryotic cell division, during which the nuclear envelope breaks down and strands of chromatin form into chromosomes.

centriole-a small, cylindrical cell organelle, seen near the nucleus in the cytoplasm of most eukaryotic cells, that divides in perpendicular fashion during mitosis, the new pair of centrioles moving ahead of the spindle to opposite poles of the cell as the cell divides: identical in internal structure to a basal body.

spindle-A network of protein fibers that forms in the cytoplasm of a cell during cell division. The spindle grows forth from the centrosomes and attaches to the chromosomes after the latter have been duplicated, and the nuclear mem brane dissolves. Once attached, the spindle fibers contract, pulling the duplicate chromosomes apart to opposite poles of the dividing cell. See more at meiosis, mitosis.
metaphase-The stage of mitosis and meiosis, following prophase and preceding anaphase, during which the chromosomes are aligned along the metaphase plate.

anaphase- the stage in mitosis or meiosis following metaphase in which the daughter chromosomes move away from each other to opposite ends of the cell.

telophase-the final stage of meiosis or mitosis, in which the separated chromosomes reach the opposite poles of the dividing cell and the nuclei of the daughter cells form around the two sets of chromosomes.

cytokinesis-the division of the cell cytoplasm that usually follows mitotic or meiotic division of the nucleus.





Cancer-A disease characterized by any of various malignant neoplasms composed of abnormal cells that tend to proliferate rapidly and invade surrounding tissue. Without treatment such as chemotherapy or radiation, cancer cells can metastasize to other body sites and cause organ failure and death.


http://www.youtube.com/watch?v=VhkQP5g4EHo