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Essay on Microorganisms | Microbiology

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❶Strictly anaerobic bacteria, on the other hand, tend to collect in the centre, whilst microaerophilic bacteria, such as some pseudomonads and spirilla, keep a certain distance from the air interface.

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Microorganisms are the tiny organisms that cannot be seen by the naked eyes. They are microscopic and are usually known for producing diseases to animals and human beings. Learning about microorganisms is important to the understanding of the environment and the ecosystem around us.

With so many technical terminologies, microorganism essay may irritate the students. Are you one of them, or do you feel that you cannot just take the essay with so many complexities?

Do not worry, you are not only a single person feeling that, we all resist writing as far as possible! You can buy essays from us and remain free of all the worries about the essay. We are not here to cheat the students and play with their life by way of plagiarized materials. We are here to make their academic life easy and successful. A microorganism essay is a scientific writings and hence it offers very low space for creativity.

You should base your ideas strictly on the experiments that have been carried out by other or that you carry out. Observation and studying the microorganism by way of microscope is one of the ways. Also reading books, journals and other materials on microorganisms is a useful way to learn more about the microorganisms. Read more on the following topics: We have collected some information you can use for your microorganism essay:.

For microorganism essay , you should ensure that you use right language with appropriate jargons based on your audience. Anyway, choose the topic that you find interesting so that you can put good time and effort to ensure that your essay appeals to the readers.

For further assistance on how to write a high quality essay, you can refer to the pages- useful prompts to help you to write your custom essay , 7 common mistakes while writing an essay paper. Our writers will not leave any ground for plagiarism. The total volume of trade in microbiological products is increasing sharply every year, and it is expected to soon become the major contributor to world trade.

Many commentators are confident that the 21st century will be the century of microbial biotechnology, just as the 20th century is the era of electronics. The importance of microorganisms in human welfare would become obvious from some selected examples given as follows: Infectious disease caused by microorganisms have been of mankind for centuries and continue to cause highly morbidity and sufferings worldwide.

Disease and death have always attracted the attention of the human mind. The emergence of acquired immunodeficiency syndrome AIDS caused by human immunodeficiency virus HIV as a major modern day scourge with tremendous public health importance has brought into limelight even those diseases which were considered rare in the past.

Applications of microbiology have given medicine the greatest success in the diagnosis prevention, and cure of disease Table 1. Production of variety of antibiotics, e. Many dairy products are manufactured, at least in part, via microbial activity. They include cheese, yogurt, buttermilk, etc. Similarly, sauerkrant, pickles and some sausages also owe their existence to microbial activity. Even more pervasive in our society are alcoholic beverages which are also based on the activities of yeasts.

We know that food spoilage by variety of microorganisms results in immense economic loss every year. The canning, frozen-food, and dried food industries exist to prepare food in such ways that they will not undergo microbial spoilage. Some microorganisms have long been used as human food, e.

More recently, efforts have been made to produce microbial biomass using low cost substrates and use it for human consumption. Since this microbial biomass is rich in protein, it is popularly called single cell protein SCP.

SCP can be produced using algae, fungi, yeasts and bacteria. The substrates used for SCP production range from CO 2 used by algae through industry effluents like whey, etc. Commercial production of SCP is mostly based on yeasts and some other fungi, including mushrooms. In most cases, SCP has to be processed to remove the excess of nucleic acids. SCP is rich in high quality protein and is rather poor in fats.

Both these features are desirable in human food. SCP provides a valuable protein-rich supplement in human diet. Their use should help bridge the gap between the requirement and the supply of proteins in human diet. It should also reduce the pressure on agricultural production systems for the supply of the required proteins. In addition, SCP production based on industrial effluents helps reduce environmental pollution.

A number of major crops are members of a plant group called legumes, which live in close association with specific bacteria that form structures called nodules on their roots. In these root nodules, atmospheric N 2 is converted to fixed nitrogen compounds that the plants can use for growth. In this way, the activities of the root nodule bacteria Rhizobium spp.

Microorganisms also play master roles in the cycling of important nutrients in plant nutrition, particularly, carbon, nitrogen and sulphur. Microbial activities in soil and water convert these elements to forms that are readily accessible to plants. Microorganisms employed to enhance the availability of nutrients like nitrogen N , and phosphors P crops are called biofertilizers. For example rhizobia from root nodules in legume crops like pulses. Similarly, phosphate is solubilized by some bacteria and by some fungi that form association with plant roots called mycorrhiza.

Several other mircoorganisms used as biofertilizer promote plant growth and protect plants from soil pathogens. Bio-fertilizers are a low cost input and they do not pollute the environment.

They also reduce the dependence on chemical fertilizers that are produced from non-renewable natural resources and pollute the environment. Some bacteria are deadly parasites of plants, animals and human beings; some live as mutualists with plants or as commensals in the alimentary canals of animals.

Bacteria eubacteria are microscopic and least differentiated living organisms, believed to be the first primitive organisms on our planet. They are the typical prokaryotes and also possess characters resembling both the plants and the animals.

Bacteria show considerable variation in characters almost themselves, they possess many characters common to all. Most of the bacteria have heterotrophic absorptive mode of nutrition, i. Some bacteria are autotrophic; they possess bacteriochlorophyll and synthesize their own food. Bacteria are usually single-called and morphologically least complex of all the living organisms.

Bacteriochlorophyll pigments, whenever present, are located within involuted cytoplasmic membranes; well organised plastids are absent. Bacterial cell wall is a dense layer surrounding the plasma membrane and functions to give shape and rigidity to the cell. The main constituent or back-bone of bacterial cell wall is peptidoglycan also known murein, muranic acid or mucopeptide , which is biochemically unique and is absent in cell walls of archea archaebacteria or any eukaryote.

A well organised nucleus, characteristic of eukaryotes, is lacking and descrete chromosomes are also absent. The nuclear material is not surrounded by nuclear membrane and is usually called nucleoid. Bacterial DNA have no histone proteins and nucleosomes.

The function of mitochondria is carried out by complex localized in folding of plasma membrane known as mesosomes. Ribosomes occur abundantly and freely in the cytoplasm of a bacterial cell. Each ribosome has a sedimentation coefficient of 70S and is made up of two subunits of 50S and 30S each consisting of roughly equal amounts of rRNA and protein.

True sexual reproduction is absent. The sexuality is completed by genetic recombination methods called conjugation, transformation and transduction. The motile bacteria possess one or more flagella.

Each flagellum is composed of eight parallel chains of flagellin molecules, a type of protein. The following categories of bacteria are recognized on the basis of diversity in their morphological features: The cocci bacteria [Fig.

They occur either singly microbacillus , in pairs diplobacillus , in chains streptobacillus , or in palisade arrangement. When the bacilli bacteria are so curved that they look like a comma, they are called vibrios Fig.

When the bacilli bacteria are coiled like a cork-screw through complete turns, they are referred to as Spirilla [Fig. In some cases, the stalk is a part of the cell Caulobacter , in others it is formed as a result of secretion from the cell Gallionella. Usually these bacteria have sticky, knob-like base that join each other forming a rosette-like structure. The whole call looks like a loot-ball. The tubular structure elongates and swells forming a new cell.

This process results in a network of globular cells, e. Some bacteria have filamentous and branched mycelial body and for a long time they were considered to be fungi. It was the prokaryotic nature of their cells that enabled the microbiologists to put them with bacteria. These filamentous bacteria Fig. Some actinomycetes are pathogenic to man, while others cause important plant diseases. Mostly these are present in soil. Actinomycetes are very important bacteria as they are one of the most important sources of antibiotics, e.

The cells of myxobacteria are cigar-shaped and usually form a colony in a common slimy mass. Though some of the gliding bacteria do not form any fruiting body, others form. At the time of fruetification the cells come closer and heap-up. The mucilaginous covering around them becomes hard and the whole structure looks a tree with the branches hearing brightly coloured oval or spherical cysts.

In each cyst hundreds of bacterial cells are present which glide out when the cyst-wall ruptures. Examples of myxobacteria are Beggiatoa, Chondromyces, etc. I and J are the bacteria having spiral-shaped body but lacking a rigid cell wall. The flexion is caused by contraction of fibrils called crista. Each end of crista is anchored in the cytoplasm. Spirochaetes are found in fresh, sea and polluted waters.

They divide by binary fission and do not produce resting spores. Examples of spirochaetes are Cristispira, Treponema, Spirochaeta etc. The study of the bacterial cell wall dates back to more than five decades when Salton and Home described the structure of cell wall for the first time; this was later confirmed by electron microscopic studies.

Cell wall is a dense layer surrounding the plasma membrane and functions to give shape and rigidity to the cell. Concentration of dissolved solutes inside a bacterial cell like that of E. This amount of pressure is counterbalanced by the cell wall.

Bacteria can be divided into two major groups, namely, gram-positive and gram-negative on the basis of differences in their cell-wall structure. The main constituent or back-bone of bacterial cell wall is peptidoglycan also known murein, muramic acid or mucopeptide which is biochemically unique and is absent in the cell walls of Archaea archaebacteria or any eukaryotc. Though the peptidoglycan is present in both gram-positive and gram-negative bacteria cell walls, it alone does not make the whole structure of the complex cell wall and is accompanied with other biochemical components.

Peptidoglycan, the main constituent or back-bone of bacterial cell wall, consists of two parts: The peptide portion is a short-chain composed of four amino acids L-alanine, D-glutamine, either L-lysine or diaminopimelic acid, and D-alanine connected with each other by piptide-linkages and hence is called tetrapeptide chain.

The two adjacent of different tetrapeptide chains are interlinked by a cross-linkage peptide interbridge. The type and extent of cross-linkages may vary among different species. In some species, the cross-linkage forms between the carboxyl group -CO- of an amino acid in one tetrapeptide chain and amino group -NH- of an amino acid in other tetrapeptide chain Fig. In others, a pentaglycine chain is used to link two tetrapeptide side chains Fig.

It is these cross-linkages that provide rigidity to the peptidoglycan which helps protecting the cell against osmotic socks exerted on it.

However, the diaminopimelic acid DAP does not occur in the peptidoglycan of all bacteria; only all gram-negative bacteria and some gram-positive bacteria possess it. Most of the gram-positive bacteria have amino acid lysine instead of DAP. Another unusual feature of the peptidoglycan i. It is because in proteins amino acids are always of L-configuration. The chemical structure of one of the repeating units of peptidoglycan is given in Fig.

The cell wall of gram-positive bacteria Bacillus, Streptococcus, etc. The remainder being made up of proteins, polysaccharides, and teichoic acid. Teichoic acids are acidic polysaccharides, which lie on the outer surface of the peptidoglycan, and are covalently bonded with it.

Their functions are not known with certainty; they are considered to affect the passage of ions, thereby help maintain the cell wall at a relatively low pH so that self- produced enzymes autolysins do not degrade the cell wall.

Other functions are also attributed to teichoic acid such as binding metals and acting as receptor sites for some viruses. The wall of gram-negative bacteria Rhizobium, Escherichia, Salmonella, etc.

The region between the inner plasma membrane and the outer membrane is called periplasmic space. The outer membrane is present outside the thin peptidoglycan layer Fig. It is a small lipoprotein covalently joined to the underlying peptidoglycan and embedded in the outer membrane by its hydrophobic end. There are, however, a special type of porin proteins present in the outer membrane. Three porin molecules cluster together and span the outer membrane to form a narrow channel through which molecules smaller than about daltons can pass.

The most unusual constituents of the outer membrane are its lipopolysaccharides LPSs. The latter are large, complex molecules consisting of three parts:


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Microorganisms play an important role in our life: helps us to digest our food, decompose wastes and participate in various cycles. They.

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Short Essay on Micro-Organisms. Article shared by. Soil contains a large number of bacteria and other microbes. Several microbes are harmful to us. They cause disease like cholera, typhoid, polio and leprosy in human beings. Some of these microbes are helpful to us. The nitrogen-fixing bacteria found in the root nodules of leguminous plants.

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Microorganisms, which include many different fungi, bacteria, and actinomycetes, are considered the architects of the soil as they have the ability to create a strong ecosystem in the soil. Microorganisms work best in communities to develop the structures for plants. ADVERTISEMENTS: In this essay we will discuss about Microorganisms. After reading this essay you will learn about: 1. Hidden World of Microorganisms 2. General Classification of Microorganisms 3. Importance in Human Welfare. Contents: Essay on the Hidden World of Microorganisms Essay on the General Classification of Microorganisms Essay on the Importance of Microorganisms in Human [ ].

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A microorganism (from the Greek: μικρός, mikros, "small" and ὀργανισμός, organismós, "organism") is a microscopic organism, which may be a single cell[1] or multicellular organism. A microorganism essay is a scientific writings and hence it offers very low space for creativity. You should base your ideas strictly on the experiments that have been carried out .