The Properties Of The Living Cell

The living cell is actually quite an interesting work of natural art. This article will give you a brief snapshot of their properties.

In your high school biology class you probably studied the life of a living cell. At the time you may have wondered why so much time has been spent studying something that the human eye cannot even see. The truth is that everything is composed of cells. Think about the hamburger you ate for lunch: that was composed of cells.

What is a cell? A cell is the smallest unit of life. The cell is the starting point for all organisms. Some living things (such as bacteria) are composed of one cell, whereas a complex organism such as the human body is composed of trillions of cells. In the multicellular animals, a group of cells makes up tissues, which make up organs, which make organ systems, which in turn form the complete animal. Without cells we would not exist.

There are three basic components of every cell: an outer membrane, a central nuclear region, and the cytoplasm in between. These elements don't make much sense if you don't know why they are important to the cell.



The cell has a membrane. The membrane surrounds the cell, isolating it from the outside. The membrane is complex and can contain many channels that allow the cell to communicate with the environment through complicated chemical interactions that happen on the scale of a few molecules at a time. The membrane also regulates the in-and-out flow of certain materials, allowing certain chemicals in (such as food) or out (such as waste), but blocking others.

Even the simplest cells have a nuclear region. Think of this region as a control center. The nuclear region is the social director for the cell. It basically tells the cell what to do and when to do it. These orders are handed down by the nucleus in the form of chemical reactions that take place in the cell.

The cytoplasm is not something from Ghostbusters, but instead it is a semifluid matrix which occupies the volume between the nuclear region and the cell membrane. Think of the cytoplasm as the cream filling. The cytoplasm, however, has a more important function: it contains the chemical wealth of the cell. The sugars, amino acids, and proteins that are used to carry out the chemical reactions of the cell are housed within the cytoplasm. All cells share this basic architecture.

Why are cells so small? Not all cells are the same size, but for the most part they are smaller than you can imagine. The reason that cells are so small is that each cell must maintain centralized control to function efficiently. If the cell was large it would take a long time to perform the tasks given by the nucleus, since the chemical reactions involved in a cell's function are fairly complicated and do not work well on a larger scale. Smaller cells also have the advantage of a greater surface area for their mass, thus allowing them to communicate with their environment. The small size of cells did not allow them to be discovered until 1665, when the first microscope was invented.

What kind of cells are there? For the most part there are Prokaryote cells and Eukaryote cells. An easy way to remember the difference is thinking of "P" standing for "prehistoric." Prokaryotes are the more basic of the two kinds of cells. A prokaryote cell is very simple in its structure and function. Bacteria are prokaryote cells. These cells have a membrane and a very simple nuclear region. There are not separate divisions in the bacterium that carry on their own chemical reactions. For the most part, in a bacteria cell, what you see is what you get.

The Eukaryote cell is the more advanced of the two, and most cells are eukaryotic in nature. The structure of these cells is much more complicated and diverse than the structure of prokaryotic cells. The most distinctive difference is that the eukaryotic cell has extensive membrane subdivisions called organelles, which are kind of like the individual organs in a human body. Each organelle of the eukaryote has its own function. For example, eukaryotic cells have lysosomes which contain digestive enzymes that play a role in cell death. Some cancer research has been linked to lysosomes, in that a gene for cancer may temporarily disable the lysosome from doing its cellular duty (i.e., killing off the cell when it is time). Thus the cancer cells divide and these bad cells never get weeded out of the body. It is thought that eukaryote cells may have evolved from the simpler prokaryote cells.

This is just the tip of the iceberg. Cellular biology is one facet of biology that is intensely studied. Cells are very important because they carry out all of life's activities. Without cells, we would not even be able to move a muscle, because the reactions that are needed to allow it to happen would not be present.

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