Monday, 30 June 2014

Types of microorganisms.

Microorganisms or microbes are microscopic organisms that exist as unicellular, multicellular, or cell clusters. Microorganims are widespread in nature and are beneficial to life, but some can cause serious harm. They can be divided into six major types: bacteria, archaea, fungi, protozoa, algae, and viruses .

Bacteria

Bacteria are unicellular organisms. The cells are described as prokaryotic because they lack a nucleus. They exist in four major shapes: bacillus (rod shape), coccus (spherical shape), spirilla (spiral shape), and vibrio (curved shape). Most bacteria have a peptidoglycan cell wall; they divide by binary fission; and they may possessflagella for motility. The difference in their cell wall structure is a major feature used in classifying these organisms.
According to the way their cell wall structure stains, bacteria can be classified as either Gram-positive or Gram-negative when using the Gram staining . 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).
According to the way they obtain energy, bacteria are classified as heterotrophs orautotrophs. Autotrophs make their own food by using the energy of sunlight orchemical reactions, in which case they are called chemoautotrophs. Heterotrophs obtain their energy by consuming other organisms. Bacteria that use decaying life forms as a source of energy are called saprophytes.

Archaea

Archaea or Archaebacteria differ from true bacteria in their cell wall structure and lack peptidoglycans. They are prokaryotic cells with avidity to extreme environmental conditions. Based on their habitat, all Archaeans can be divided into the following groups: methanogens (methane-producing organisms), halophiles (archaeans that live in salty environments), thermophiles (archaeans that live at extremely hot temperatures), and psychrophiles (cold-temperature Archaeans). Archaeans use different energy sources like hydrogen gas, carbon dioxide, and sulphur. Some of them use sunlight to make energy, but not the same way plants do. They absorb sunlight using their membrane pigment, bacteriorhodopsin. This reacts with light, leading to the formation of the energy molecule adenosine triphosphate (ATP).

Fungi

Fungi (mushroom, molds, and yeasts) are eukaryotic cells (with a true nucleus). Most fungi are multicellular and their cell wall is composed of chitin. They obtain nutrients by absorbing organic material from their environment (decomposers), through symbiotic relationships with plants (symbionts), or harmful relationships with a host (parasites). They form characteristic filamentous tubes called hyphae that help absorb material. The collection of hyphae is called mycelium. Fungi reproduce by releasing spores.

Protozoa

Protozoa are unicellular aerobic eukaryotes. They have a nucleus, complex organelles, and obtain nourishment by absorption or ingestion through specialized structures. They make up the largest group of organisms in the world in terms of numbers, biomass, and diversity. Their cell walls are made up ofcellulose. Protozoa have been traditionally divided based on their mode of locomotion: flagellates produce their own food and use their whip-like structure to propel forward, ciliates have tiny hair that beat to produce movement, amoeboids have false feet or pseudopodia used for feeding and locomotion, and sporozoans are non-motile. They also have different means of nutrition, which groups them as autotrophs or heterotrophs.

Algae

Algae, also called cyanobacteria or blue-green algae, are unicellular or multicellular eukaryotes that obtain nourishment by photosynthesis. They live in water, damp soil, and rocks and produce oxygen and carbohydrates used by other organisms. It is believed that cyanobacteria are the origins of green land plants.

Viruses

Viruses are noncellular entities that consist of a nucleic acid core (DNA or RNA) surrounded by a protein coat. Although viruses are classified as microorganisms, they are not considered living organisms. Viruses cannot reproduce outside a host cell and cannot metabolize on their own. Viruses often infest prokaryotic and eukaryotic cells causing diseases.
Gram Stain
This is a microscopic image of a Gram stain of mixed Gram-positive cocci (Staphylococcus aureus, purple) and Gram-negative bacilli (Escherichia coli, red).
Types of microorganisms
This tree of life shows the different types of microorganisms.
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Classification of Microorganisms

 KEY TERM GLOSSARY

Anaerobe
 
An anaerobic organism; one that does not require oxygen to sustain its metabolic processes.
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Gram-negative
 
Gram-negative bacteria are bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain (commonly safranin) is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color.
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adenosine triphosphate
 
Adenosine-5'-triphosphate (ATP) is a multifunctional nucleoside triphosphate used in cells as a coenzyme. It is often called the "molecular unit of currency" of intracellular energy transfer. a multifunctional nucleoside triphosphate used in cells as a coenzyme, often called the "molecular unit of energy currency" in intracellular energy transfer a nucleotide that occurs in muscle tissue and is used as a source of energy in cellular reactions and in the synthesis of nucleic acids
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aerobic
 
Living or occurring only in the presence of oxygen. Occurring only in the presence of oxygen; aerobic exercise is typical of activities requiring endurance and sustained muscle contractions. Such activities rely mainly on Type I (slow-twitch muscles). Living or occurring only in the presence of oxygen (e.g. aerobic bacteria) living or occurring only in the presence of oxygen Involving or improving oxygen consumption by the body (e.g. aerobic exercise).
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anaerobes
 
Organisms that do not require oxygen for growth.
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anaerobic
 
Without oxygen; especially of an environment or organism. Without oxygen; Anaerobic respiration, typical of sprinting and weight lifting, prioritizes the use of Type II (fast-twitch) muscles fibers
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archaea
 
a taxonomic domain of single-celled organisms lacking nuclei that are fundamentally from bacteria.The Archaea are a group of single-celled microorganisms. They have no cell nucleus or any other membrane-bound organelles within their cells. a taxonomic domain of single-celled organisms lacking nuclei, formerly called archaebacteria but now known to differ fundamentally from bacteria. a taxonomic domain of single-celled organisms lacking nuclei, formerly called archaebacteria, but now known to differ fundamentally from bacteria
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autotroph
 
Any organism that can synthesize its food from inorganic substances, using heat or light as a source of energy. an organism that can synthesize its food from inorganic substances, using heat or light as a source of energy. Any organism that can synthesize its food from inorganic substances, using heat or light as a source of energy
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avidity
 
The measure of the synergism of the strength of individual interactions between proteins. the measure of the synergism of the strength individual interactions between proteins
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bacteria
 
A type, species, or strain of bacterium. Bacteria constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals. Bacteria were among the first life forms to appear on Earth, and are present in most habitats on the planet.
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bacterium
 
A single celled organism with no nucleus.
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biomass
 
The total mass of all living things within a specific area or habitat. the total mass of all living things within a specific area, habitat, etc.
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carbohydrates
 
A major class of foods that includes sugars and starches.
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cell wall
 
A thick, fairly rigid layer formed around individual cells of bacteria, Archaea, fungi, plants, and algae, the cell wall is external to the cell membrane and helps the cell maintain its shape and avoid damage.
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cellulose
 
A complex carbohydrate that forms the main constituent of the cell wall in most plants and is important in the manufacture of numerous products, such as paper, textiles, pharmaceuticals, and explosives.a complex carbohydrate that forms the main constituent of the cell wall in most plants
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chemical reactions
 
Processes that lead to the transformation of one set of chemical substances to another.
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chitin
 
A complex polysaccharide, a polymer of N-acetylglucosamine, found in the exoskeletons of arthropods and in the cell walls of fungi; thought to be responsible for some forms of asthma in humans. a complex polysaccharide, a polymer of N-acetylglucosamine, found in the exoskeletons of arthropods and in the cell walls of fungi; thought to be responsible for some forms of asthma in humans
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cyanobacteria
 
Cyanobacteria, also known as blue-green bacteria, blue-green algae, and Cyanophyta, is a phylum of bacteria that obtain their energy through photosynthesis. photosynthetic prokaryotic microorganisms, of phylum Cyanobacteria, once known as blue-green algae
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ecosystem
 
The interconnectedness of plants, animals, and microbes with each other and their environment. a system formed by an ecological community and its environment that functions as a unit
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ecosystems
 
Communities of living organisms (plants, animals and microbes) in conjunction with the nonliving components of their environment (things like air, water, and mineral soil), interacting as a system; linked together through nutrient cycles and energy flows.
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eukaryote
 
Any of the single-celled or multicellular organisms, of the taxonomic domain Eukaryota, whose cells contain at least one distinct nucleus.
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eukaryotes
 
A eukaryote is an organism whose cells contain complex structures enclosed within membranes. Eukaryotes may more formally be referred to as the taxon Eukarya or Eukaryota. The defining membrane-bound structure that sets eukaryotic cells apart from prokaryotic cells is the nucleus, or nuclear envelope, within which the genetic material is carried.
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eukaryotic
 
Having complex cells in which the genetic material is organized into membrane-bound nuclei.
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facultative
 
Not obligate; optional, discretionary or elective
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flagella
 
A flagellum is a lash-like appendage that protrudes from the cell body of certain prokaryotic and eukaryotic cells.
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habitat
 
A specific place or natural conditions in which a plant or animal lives. a specific place or natural conditions in which a plant or animal lives
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halophile
 
An organism that lives and thrives in an environment of high salinity, often requiring such an environment; a form of extremophile. an organism that lives and thrives in an environment of high salinity, often requiring such an environment; a form of extremophile
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health
 
The state of being free from physical or psychological disease, illness, or malfunction; wellness.
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heterotroph
 
An organism which requires an external supply of energy in the form of food as it cannot synthesize its own. An organism that requires an external supply of energy in the form of food as it cannot synthesize its own. an organism that requires an external supply of energy in the form of food, as it cannot synthesize its own
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host
 
A cell or organism which harbors another organism or biological entity, usually a parasite.
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membrane
 
A flexible enclosing or separating tissue forming a plane or film and separating two environments (usually in a plant or animal).
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microbes
 
A microorganism or microbe is a microscopic organism that comprises either a single cell (unicellular), cell clusters, or multicellular relatively complex organisms.
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microorganism
 
An organism that is too small to be seen by the unaided eye, especially a single-celled organism, such as a bacterium.
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microorganisms
 
A microorganism or microbe is a microscopic organism that comprises either a single cell (unicellular), cell clusters, or multicellular relatively complex organisms.
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molecules
 
A molecule is an electrically neutral group of two or more atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their lack of electrical charge. However, in quantum physics, organic chemistry, and biochemistry, the term molecule is often used less strictly, also being applied to polyatomic ions.
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movement
 
Physical motion between points in space.
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nucleic acid
 
Any acidic, chainlike biological macromolecule consisting of repeating units of phosphoric acid, sugar, and purine and pyrimidine bases; they are involved in the preservation, replication, and expression of hereditary information in every living cell.
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organelle
 
a specialized structure found inside cells that carries out a specific life process (e.g., ribosomes, vacuoles) A specialized structure found inside cells that carries out a specific life process (e.g. ribosomes, vacuoles).
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organic
 
relating to the compounds of carbon, relating to natural products relating to the compounds of carbon, and relating to natural products
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organisms
 
An organism is any contiguous living system (such as animal, fungus, micro-organism, or plant). In at least some form, all types of organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homeostasis as a stable whole.
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pathogenic
 
Able to cause harmful disease.
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photosynthesis
 
The process by which plants and other photoautotrophs generate carbohydrates and oxygen from carbon dioxide, water, and light energy in chloroplasts. the process by which plants and other photoautotrophs generate carbohydrates and oxygen from carbon dioxide, water, and light energy in chloroplasts
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planet
 
A body which orbits the Sun directly and is massive enough to be in hydrostatic equilibrium (effectively meaning a spheroid) and to dominate its orbit. The eight planets in the Solar System are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Pluto was considered a planet until 2006 and has now been reclassified as a dwarf planet. A large body which directly orbits any star (or star cluster) but which has not attained nuclear fusion.
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protein
 
any of numerous large, complex naturally-produced molecules composed of one or more long chains of amino acids, in which the amino acid groups are held together by peptide bonds Any of numerous large, complex naturally-produced molecules composed of one or more long chains of amino acids, in which the amino acid groups are held together by peptide bonds. Proteins are large biological molecules consisting of one or more chains of amino acids.
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protozoa
 
Protozoa are a diverse group of unicellular eukaryotic organisms, many of which are motile. Originally, protozoa had been defined as unicellular protists with animal-like behavior, e.g., movement. Protozoa were regarded as the partner group of protists to protophyta, which have plant-like behaviour, e.g., photosynthesis. Protozoa are a diverse group of unicellular eukaryotic organisms, many of which are motile. Originally, protozoa had been defined as unicellular protists with animal-like behavior, e.g., movement. Protozoa were regarded as the partner group of protists to protophyta, which have plant-like behavior, e.g., photosynthesis.
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psychrophile
 
An organism that can live and thrive at temperatures much lower than normal; a form of extremophile.
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reaction
 
An action or statement in response to a stimulus or other event. A transformation in which one or more substances is converted into another by combination or decomposition A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that strictly involve the motion of electrons in the forming and breaking of chemical bonds between atoms, and can often be described by a chemical equation.
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spore
 
A thick resistant particle produced by a bacterium or protist to survive in harsh or unfavorable conditions. a reproductive particle, usually a single cell, released by a fungus, alga, or plant that may germinate into another
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symbiotic
 
Of a relationship with mutual benefit between two individuals or organisms. of a relationship with mutual benefit between two individuals or organisms
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thermophile
 
An organism that lives and thrives at relatively high temperatures; a form of extremophile; many are members of the Archaea. An organism — a type of extremophile — that thrives at relatively high temperatures, between 45 and 122 °C (113 and 252 °F). Many thermophiles are archaea. Thermophilic eubacteria are suggested to have been among the earliest bacteria.
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vibrio
 
Any of several bacteria, of the genus Vibrio, shaped like a curved rod.
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