Bacteria :: Science Chemistry Biology Experiment Essays

Bacteria Bacteria atomic number 18 the most common and ancient microorganisms on earth. Most bacteria are microscopic, measuring 1 micron in length. However, colonies of bacteria grown in a laboratory petri dish can be seen with the unaided eye. There are many divisions and classifications of bacteria that assist in identifying them. The first two types of bacteria are archaebacteria and eubacteria. Both groups shake off common ancestors dating to more than 3 billion days ago. Archaebacteria live in environments where, because of the high temperature, no other life can grow. These environments include hot springs and areas of volcanic activity. They contain lipids but lack definite chemicals in their cell wall. Eubacteria are all other bacteria. Most of them are phototrophic, i.e. they use the suns energy as food through the process of photosynthesis. some other classification of bacteria is according to their need of oxygen to live. Those who do require oxygen to live are considered aerobes. The bacteria who dont use oxygen to live are known as anaerobes. The shape of specific bacteria provides for the next step in the identification process. Spherical bacteria are called cocci the bacteria that have a rodlike shape are known as bacilli corkscrew shaped bacteria are spirilla and filamentous is the term for bacteria with a threadlike appearance. Hans Christian Joachim Gram, a Danish microbiologist, developed a method for distinguishing bacteria by their different reaction to a stain. The process of applying Grams stain is as follows the bacteria are stained with a violet dye and treated with Grams solution (1 part iodine, 2 parts potassium iodide, and 300 parts water). ethyl alcohol is then applied to the medium the bacteria will either preserve the blue color of the original dye or they will win a red hue. The blue colored bacteria are gram-positive the red bacteria are identified as gram-negative. Bacteria contain deoxyribonucleic aci d (deoxyribonucleic acid) still like all cells. However, in bacteria the DNA is arranged in a circular fashion rather than in strands. Bacteria as well contain ribosomes which, like in eukaryotic cells, provide for protein synthesis. In order for a bacterium to attach itself to a surface, it requires the aid of pili, or hairlike growths. Bacteria, just like sperm cells, have flagella which assist in movement. But, sperm cells only have one flagellum, whereas bacteria contain flagella at several locations throughout their automobile trunk surface.