Mononucleus - Bacteria

Essay by Andy4High School, 10th gradeA+, December 1996

download word file, 6 pages 4.0

Downloaded 90 times

Good Essay none


The smallest living things on earth are the prokaryotic cells. Bacteria fall into the Monera Kingdom. They have a single DNA molecule in the cytoplasm. Almost all monerans have a cell wall that protects the cell and gives it its shape. Some monerans have a layer outside the cell wall called the capsule. This helps the cell cling to surfaces.

A typical bacterium is about 2 micrometers long. Inside the cell, there are nucleic acids, enzymes, and other substances necessary to carry out the cells life process.

Bacterium have long , thin, hairlike structures called flagella. They act as a propeller, as they rotate and move in response to chemical stimulation. Some have strands of pili , which enables them to stick itself to a surface.

Some shell shapes important in classifying monera are: spherical cells, called cocci ; Rod shaped cells called bacilli, and spiral shaped cells called spirilli.

There are over 16,000 species of monerans.

Bacteria Showing Flagella Disease Causing Bacteria

Two main groups of bacteria exist: the saprophytes, which live on dead animal and vegetable matter; and the symbionts, which live on or in living animal or vegetable matter. Saprophytes are important because they decompose dead animals and plants into their constituting elements, making them available as food for plants. Symbiotic bacteria are a normal part of many human tissues, including the alimentary canal and the skin, where they may be essential to certain processes. Bacteria are involved in the spoilage of meat, wine, vegetables, and milk and other dairy products. Bacterial action may render such foods unpalatable by changing their composition. Bacterial growth in foods can also lead to food poisoning such as that caused by botulism. On the other hand, bacteria are of great importance in many industries. The fermentative...