There are three basic shapes. i) Monococcus which is a single-celled round-shaped bacteria. Types of Bacteria based on shape and reaction of their cell walls to certain stains. Spherical (cocci) 2. These facultative anaerobes and can survive without oxygen. Flagella are appendages of movement for the bacteria. Not all bacteria have flagella but motile bacteria have flagella. Coccus is one of the three primary shapes of bacteria. ♦ Amphitrichous bacteria: Two flagella on both sides of the cell, ♦ Peritrichous bacteria: Many flagella at different points, ♦ Lophotrichous bacteria: Flagella at one pole or point of the cell. Cocci bacteria appear spherical or oval in shape. Places Where Bacteria are Found. 0.0 0 votes 0 votes Rate! arrangements. Hence taking too many antibiotics kills the friendly bacteria in our gut causing problems to us. Like, ♦ Thermophilic (thermo+phyllic=temperature loving); Thermophilic bacteria are those which can survive at a high temperature of 45 to 60-degree temperatures, ♦ mesothermic (medium+thermic= medium temperature) can survive at 25 to 45 degrees. Don't forget to answer the questions on the back! Round-shaped bacteria. When a bacteria culture is added with Gram’s stain, gram-positive bacteria show violet color, while gram-negative bacteria show saffron color. 1.3.1 Size. ♦ Hypothermic (hypo = low ) These bacteria survive at low temperatures like 8 degrees or even less. So, the bacterial species which take up the blue color during gram staining are called gram +ve and those which take up an orange are called gram -ve bacteria. The major characteristics of Bacteria are based on their size, shape and. The three basic shapes of bacteria are spherical, rod shaped and spiral. Examples include Acetobacter. Common bacterial cell shapes include cocci (spherical), bacilli (rod-shaped), spiral, and vibrio. 7 min. Either they may remain as a single cell or may aggregate together for various configurations. CLASSIFICATION BASED ON GRAM STAINING . Cocci can be round, oval or elongated or bean-shaped. This spirochete bacterium (Treponema pallidum) is spirally twisted in form, elongated and appearing thread-like (yellow). I mean the vocabulary is a less inappropriate. For more details, see our Privacy Policy. Cocci (or coccus for a single cell) are round cells, sometimes slightly flattened when they are adjacent to one another. Bacteria (the singular is a bacterium) are single cell organisms that can live in different media. 4. Spiral. 11 min. The flagella are present all over the cell wall. Helically curved rods (spirilla) 4. Classification of Bacteria on the Basis of Shape. The Cell Cycle Resists Shape Changes Once a particular shape is adopted, bacteria have a vested interest in keeping it; and the major incentive for doing so is to maintain a consistent relationship between cytoplasmic volume and surface area so that cell cycle events can be coordinated properly. A number of species of vibrio bacteria are pathogens and are associated with food poisoning. Gram stain is used to classify these bacteria based on the variation in the layers. Bacterial morphology diagram. Bacilli bacteria arranged like a long chain. Curved with one or more complete turns (helical)Furthermore, some other forms of bacteria, especially cocci, may appear in characteristic arrangements or groups: 1. They exist in multiple shapes. A single bacterium can replicate very quickly, producing large numbers of identical cells that form a colony. They are further as two types. Before the advent of DNA sequencing, scientists classified bacteria according to their shapes and other biochemical properties. They get their nutrition from the host. Classification of bacteria on the basis of shape: - In the year 1872 scientist Cohn classified bacteria to 4 major types depending on their shapes are as follow: – 1) Cocci: These types of bacteria are unicellular, spherical or elliptical shape. The gram staining helps in the differentiation of bacteria as gram-positive and gram-negative. Figure 1. This nitrogen acts as a fertilizer to plant. 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Some can survive without oxygen. Remember to follow the rules for writing scientific names-- the blank line does not as the underline! The following are the main types of bacteria based on different shapes. Either they may remain as a single cell … Use the classification key to identify the bacteria, drawn at the bottom of the page, based on their shape. Regina Bailey is a board-certified registered nurse, science writer and educator. They differ from autotrophs in that they do not need sunlight. Remember to follow the rules for writing scientific names-- the blank line does not as the underline! Another example is Enterobacteria in the intestine. Bacteria as prokaryotes. Bacteria can grow at cold temperatures and even hot temperatures besides normal room temperatures. Cohn divided the bacterial into four types based on their shapes in 1872. ♦ Pathogenic bacteria: (patho+genisis =disease + causing) These are bacteria responsible for diseases in humans and plants. After what seemed like an hour, the doctor would look at me for two minutes, swab the back of my throat and declare that I had strep throat. Bacteria Types or Classification Bacteria are classified into three groups based on their shape such as; Coccus: These are spherical or round in shape. The major characteristics of Bacteria are based on their size, shape and. As a microbiologist, that short diagnosis actually tells me a lot about the bacteria that are making my throat scratchy and sore. e) Pleomorphism: Though most bacteria have a specific shape, some do not. The shape of the bacteria resembles a comma. Bacteria are unicellular organisms present in the entire biosphere. Bacteria are divided into Gram- negative and Gram-positive on the basis of their cell wall structure. Groups of two or a pair (Diplococci) 2. Bacterial morphology (size, shape and arrangement of bacterial cells) is one of the mostly used feature for the differentiation of various bacterial species. Two bacteria cells stick together. Ex:  Rhizobium bacteria in leguminous plants. Bacteria can be further divided based on their response to gaseous oxygen into the following groups: aerobic (living in the presence of oxygen), anaerobic (living without oxygen), and facultative anaerobes (can live in both environments). I remember getting sick as a kid and having to sit in the doctor's office. These cells resemble long, twisted coils. Rod-shaped bacteria. This diagram depicts the numerous shapes of bacteria. in god we trust. 11 min. Bacilli (Rod … 18 min. Comma-shaped bacteria. They can also be present as four-celled as a tetrad. Arrangements of Cocci. ii) Diplobaciullus: These are a pair of rod-shaped bacteria. Like it? Cocci are bacteria that are spherical or ovoid in shape. There are three basic shapes. National Institutes of Health/Stocktrek Images/Getty Images. Bacteria can exist as single cells, in pairs, chains or clusters.