How Cell Processes Are Regulated by Clementine Tucker & Lois Sakany

Author:Clementine Tucker & Lois Sakany
Language: eng
Format: epub
ISBN: 9781622758081
Publisher: Britannica Educational Publishing
Published: 2015-02-06T16:00:00+00:00

Adenosine triphosphate (ATP) is the power source of many biochemical reactions. It is produced in the cell structures and systems listed on the left to energize the important life processes listed on the right. Encyclopædia Britannica, Inc.

HOW CELLS GROW AND DIVIDE

One of the most important elements of a cell’s existence is its ability to grow and reproduce itself. As with all living things, cells have a life cycle of growth, maintenance, reproduction, and death. If a multicellular organism is in a growth phase, more cells are needed as it increases in size. New cells are also required to replace worn-down cells or repair damaged ones. While prokaryotic organisms reproduce using a simple form of division known as binary fission, cell division is more complex in eukaryotic organisms.

Most eukaryotic cells undergo a process of cell division known as mitosis, in which one cell divides into two identical “daughter” cells. The rate of mitosis often depends on the type of cell and its function. For example, cells that line the intestinal tracks of animals live very short lives because their environment is very hostile. Such cells divide frequently to compensate for their short life spans. Other cells, such as nerve cells, rarely undergo mitosis.

With each cell, there are regulatory mechanisms that instruct the cell whether or not to divide. One of those mechanisms, known as contact inhibition, is triggered when cells become so numerous that they begin to crowd each other. Such crowding causes a chemical message to be sent from cell to cell to inhibit mitosis. If such a mechanism were lacking, the cells would continue to divide and crowd each other, endangering the survival of the organism. Cancer is an example of a disease in which cells have lost the feedback mechanism that limits reproduction.

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