Readily observed by Darkfield microscope (Figure7.3). Spiral bacteria areįar too thin to be seen with the standard Brightfield microscope but are Although these twoĪre similar in shape spirochetes are flexible in nature. (singular spirillum) and spirochetes (agent of syphilis). Spiral bacteria: They are divided into two groups, spirilla.These cells are called vibrios as in Vibrio cholera. Side by side like matchsticks (pallisade arrangement). Some form trichomes, which are similar to chains. Subtilis) or in the form of chains ( Streptobacilli). Singles or in pairs (diplobacilli, Example: Bacillus Not arranged in patterns as complex as those of cocci and mostly occur as Stumpy that they appear ovoid and are referred to as coccobacilli. Usually ranging between 1 and 10 μm in length. Bacilli are rod shaped organism (Singular, bacillus = stick).(diplococci), in groups of four (tetracocci), in clusters ( Staphylococcus), in a bead like chain ( Streptococci) or in cuboidal arrangement of cells ( Sarcinae). Some are parasitic, which means they live. They live in a wide variety of moist habitats including fresh water, marine environments and the soil. With the parents even after cell division. They come in many different shapes and sizes ranging from an Amoeba which can change its shape to Paramecium with its fixed shape and complex structure. On the plane of cellular division and whether daughter cells remain together Cocci appear in several characteristic arrangements, depending. Particular species or genus but there are bacterial cells that are pleomorphic Typicalīacterial cells are spherical (called cocci), straight rods (called bacilli)Īnd helically curved rods (called spiral). The shape of a bacterium is governed by its rigid cell wall.
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