Cell Division and The Cell Cycle Help (page 2)

By — McGraw-Hill Professional
Updated on Aug 30, 2011

Mutation and Biological Disorder in Cells - Cancer and Abnormal Organelles

Cancer: A Severe Disorder of Mitosis

In a normal mitosis, the orderly duplication and division of chromosomes, along with the division of the cytoplasm, creates two identical daughter cells. Both of these daughter cells are normal, as well. Thus, they go about doing whatever body task they have been genetically programmed to perform. Epithelial cells, for example, frequently divide and replace themselves with daughters, each daughter cell in turn performing a body covering or cavitylining function.

But what can happen if an abnormal “change” ( mut ) or mutation (mew- TAY -shun) in the genetic program occurs? One of the really bad results can be cancer! The English meaning (and the astrological sign) for cancer, of course, is the “crab”! An alternate translation for cancer is “creeping ulcer.”

Cancer is like a stubborn crab that can afflict either epithelial tissues (like the skin) or connective tissues (such as bone). When a person has a cancer, it is like a crab with pinchers, because it seems to hold on and not let go, making it very difficult to treat! Even worse, cancer has the characteristics of a creeping ulcer, because it often spreads from one affected site of the body, to many other sites. Small wonder, then, that various forms of cancer are a leading cause of death in many countries around the world.

The exact cause of cancer in human beings, unfortunately, is still unknown. But various chemical agents, called carcinogens (car- SIN -oh-jens), are suspected cancer or “crab” ( carcin ) “producers” (- gens ). Prominent among these suspected carcinogens are the poisonous or toxic chemicals present in cigarette smoke, which are thought to be the leading cause of lung cancer. The carcinogens may trigger abnormal changes (mutations) in the DNA of epithelial or connective tissue cells. The mutations create errors in the genetic program of the Cell Cycle, such that the resulting daughter cells are highly abnormal. The mutated, cancerous daughter cells have a largely unregulated, disorganized, and extremely rapid rate of mitosis. When these cancerous cells form larger tumors, the tumors interfere with the function and nutrition of normal cells. Eventually, the normal tissue cells die or are crowded out. If this process goes on long enough, the cell metabolism of the affected person may be so abnormally changed that the person dies.

Abnormal Organelles: Biological Disorder in Cells

Various normal organelles suggests the presence of Biological Order within cells. In general, such an order or pattern supports and maintains the health and survival of the cell.

What happens, however, when a cell organelle becomes abnormal or damaged? Certainly, one would expect to see some type of associated illness or cellular problem. Consider, for example, the condition called cell autolysis (aw- TAH -luh-sis) or “self breakdown” of a cell. When a particular cell is dying, dozens of its lysosomes may rupture simultaneously. This rupturing releases thousands of stored digestive enzyme molecules. When such a huge number of these powerfully dissolving enzymes are present at the same time, they break down the whole cell. Cell autolysis thereby often serves to remove dead or dying cells from otherwise healthy body tissue. Unnecessary (and perhaps disruptive) build-up of extra dead cells is prevented.

Practice problems for these concepts can be found at: Cells: The “Little Chambers” In Plants And Animals Test

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