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Eukaryotic cells have evolved anendomembranesystem, containing membrane-bound organelles involved in transport. These include vesicles, the endoplasmic reticulum, and the Golgi apparatus. | https://openstax.org/books/microbiology/pages/3-summary |
Thesmooth endoplasmic reticulumplays a role in lipid biosynthesis, carbohydrate metabolism, and detoxification of toxic compounds. Therough endoplasmic reticulumcontains membrane-bound 80S ribosomes that synthesize proteins destined for the cell membrane | https://openstax.org/books/microbiology/pages/3-summary |
TheGolgi apparatusprocesses proteins and lipids, typically through the addition of sugar molecules, producing glycoproteins or glycolipids, components of the plasma membrane that are used in cell-to-cell communication. | https://openstax.org/books/microbiology/pages/3-summary |
Lysosomescontain digestive enzymes that break down small particles ingested byendocytosis, large particles or cells ingested byphagocytosis, and damaged intracellular components. | https://openstax.org/books/microbiology/pages/3-summary |
Thecytoskeleton, composed ofmicrofilaments,intermediate filaments, andmicrotubules, provides structural support in eukaryotic cells and serves as a network for transport of intracellular materials. | https://openstax.org/books/microbiology/pages/3-summary |
Centrosomesare microtubule-organizing centers important in the formation of the mitotic spindle in mitosis. | https://openstax.org/books/microbiology/pages/3-summary |
Mitochondriaare the site of cellular respiration. They have two membranes: an outer membrane and an inner membrane with cristae. The mitochondrial matrix, within the inner membrane, contains the mitochondrial DNA, 70S ribosomes, and metabolic enzymes. | https://openstax.org/books/microbiology/pages/3-summary |
The plasma membrane of eukaryotic cells is structurally similar to that found in prokaryotic cells, and membrane components move according to the fluid mosaic model. However, eukaryotic membranes contain sterols, which alter membrane fluidity, as well as glycoproteins and glycolipids, which help the cell recognize othe... | https://openstax.org/books/microbiology/pages/3-summary |
In addition to active transport and passive transport, eukaryotic cell membranes can take material into the cell viaendocytosis, or expel matter from the cell viaexocytosis. | https://openstax.org/books/microbiology/pages/3-summary |
Cells of fungi, algae, plants, and some protists have acell wall,whereas cells of animals and some protozoans have a stickyextracellular matrixthat provides structural support and mediates cellular signaling. | https://openstax.org/books/microbiology/pages/3-summary |
Eukaryotic flagella are structurally distinct from prokaryotic flagella but serve a similar purpose (locomotion).Ciliaare structurally similar to eukaryotic flagella, but shorter; they may be used for locomotion, feeding, or movement of extracellular particles. | https://openstax.org/books/microbiology/pages/3-summary |
Prokaryotes are unicellular microorganisms whose cells have no nucleus. | https://openstax.org/books/microbiology/pages/4-summary |
Prokaryotes can be found everywhere on our planet, even in the most extreme environments. | https://openstax.org/books/microbiology/pages/4-summary |
Prokaryotes are very flexible metabolically, so they are able to adjust their feeding to the available natural resources. | https://openstax.org/books/microbiology/pages/4-summary |
Prokaryotes live incommunitiesthat interact among themselves and with large organisms that they use as hosts (including humans). | https://openstax.org/books/microbiology/pages/4-summary |
The totality of forms of prokaryotes (particularly bacteria) living on the human body is called the human microbiome, which varies between regions of the body and individuals, and changes over time. | https://openstax.org/books/microbiology/pages/4-summary |
The totality of forms of prokaryotes (particularly bacteria) living in a certain region of the human body (e.g., mouth, throat, gut, eye, vagina) is called themicrobiotaof this region. | https://openstax.org/books/microbiology/pages/4-summary |
Prokaryotes are classified into domains Archaea and Bacteria. | https://openstax.org/books/microbiology/pages/4-summary |
In recent years, the traditional approaches to classification of prokaryotes have been supplemented by approaches based on molecular genetics. | https://openstax.org/books/microbiology/pages/4-summary |
Proteobacteriais a phylum of gram-negative bacteria discovered by Carl Woese in the 1980s based on nucleotide sequence homology. | https://openstax.org/books/microbiology/pages/4-summary |
Proteobacteria are further classified into the classes alpha-, beta-, gamma-, delta- and epsilonproteobacteria, each class having separate orders, families, genera, and species. | https://openstax.org/books/microbiology/pages/4-summary |
Alphaproteobacteriainclude several obligate and facultative intracellular pathogens, including the rickettsias. Some Alphaproteobacteria can convert atmospheric nitrogen to nitrites, making nitrogen usable for other forms of life. | https://openstax.org/books/microbiology/pages/4-summary |
Betaproteobacteriaare a diverse group of bacteria that include human pathogens of the genusNeisseriaand the speciesBordetella pertussis. | https://openstax.org/books/microbiology/pages/4-summary |
Gammaproteobacteriaare the largest and the most diverse group of Proteobacteria. Many are human pathogens that are aerobes or facultative anaerobes. Some Gammaproteobacteria areentericbacteria that may be coliform or noncoliform.Escherichia coli, a member of Gammaproteobacteria, is perhaps the most studied bacterium. | https://openstax.org/books/microbiology/pages/4-summary |
Deltaproteobacteriamake up a small group able to reduce sulfate or elemental sulfur. Some are scavengers and form myxospores, with multicellular fruiting bodies. | https://openstax.org/books/microbiology/pages/4-summary |
Epsilonproteobacteriamake up the smallest group of Proteobacteria. The generaCampylobacterandHelicobacterare human pathogens. | https://openstax.org/books/microbiology/pages/4-summary |
Gram-negative nonproteobacteria include the taxaspirochetes; theChlamydia,Cytophaga,Fusobacterium,Bacteroidesgroup; Planctomycetes; and many representatives ofphototrophic bacteria. | https://openstax.org/books/microbiology/pages/4-summary |
Spirochetes are motile, spiral bacteria with a long, narrow body; they are difficult or impossible to culture. | https://openstax.org/books/microbiology/pages/4-summary |
Several genera of spirochetes contain human pathogens that cause such diseases as syphilis and Lyme disease. | https://openstax.org/books/microbiology/pages/4-summary |
Cytophaga,Fusobacterium, andBacteroidesare classified together as a phylum called theCFB group. They are rod-shaped anaerobic organoheterotrophs and avid fermenters.Cytophagaare aquatic bacteria with the gliding motility.Fusobacteriainhabit the human mouth and may cause severe infectious diseases.Bacteroidesare present... | https://openstax.org/books/microbiology/pages/4-summary |
Planctomycetes are aquatic bacteria that reproduce by budding; they may form large colonies, and develop a holdfast. | https://openstax.org/books/microbiology/pages/4-summary |
Phototrophic bacteria are not a taxon but, rather, a group categorized by their ability to use the energy of sunlight. They include Proteobacteria and nonproteobacteria, as well as sulfur and nonsulfur bacteria colored purple or green. | https://openstax.org/books/microbiology/pages/4-summary |
Sulfur bacteria perform anoxygenic photosynthesis, using sulfur compounds as donors of electrons, whereas nonsulfur bacteria use organic compounds (succinate, malate) as donors of electrons. | https://openstax.org/books/microbiology/pages/4-summary |
Some phototrophic bacteria are able to fix nitrogen, providing the usable forms of nitrogen to other organisms. | https://openstax.org/books/microbiology/pages/4-summary |
Cyanobacteriaare oxygen-producing bacteria thought to have played a critical role in the forming of the earthâs atmosphere. | https://openstax.org/books/microbiology/pages/4-summary |
Gram-positive bacteria are a very large and diverse group of microorganisms. Understanding their taxonomy and knowing their unique features is important for diagnostics and treatment of infectious diseases. | https://openstax.org/books/microbiology/pages/4-summary |
Gram-positive bacteria are classified intohigh G+C gram-positiveandlow G+C gram-positivebacteria, based on the prevalence of guanine and cytosine nucleotides in their genome | https://openstax.org/books/microbiology/pages/4-summary |
Actinobacteria is the taxonomic name of the class of high G+C gram-positive bacteria. This class includes the generaActinomyces, Arthrobacter, Corynebacterium, Frankia, Gardnerella, Micrococcus, Mycobacterium, Nocardia,Cutibacterium, Rhodococcus,andStreptomyces. Some representatives of these genera are used in industry... | https://openstax.org/books/microbiology/pages/4-summary |
Examples of high G+C gram-positive bacteria that are human pathogens includeMycobacteriumtuberculosis, which causes tuberculosis;M. leprae, which causes leprosy (Hansenâs disease); andCorynebacteriumdiphtheriae, which causes diphtheria. | https://openstax.org/books/microbiology/pages/4-summary |
Clostridiaspp. are low G+C gram-positive bacteria that are generally obligate anaerobes and can form endospores. Pathogens in this genus includeC.perfringens(gas gangrene),C. tetani(tetanus), andC. botulinum(botulism). | https://openstax.org/books/microbiology/pages/4-summary |
Lactobacillales include the generaEnterococcus,Lactobacillus,Leuconostoc, andStreptococcus. Streptococcusis responsible for many human diseases, including pharyngitis (strep throat), scarlet fever, rheumatic fever, glomerulonephritis, pneumonia, and other respiratory infections. | https://openstax.org/books/microbiology/pages/4-summary |
Bacilli is a taxonomic class of low G+C gram-positive bacteria that include rod-shaped and coccus-shaped species, including the generaBacillusandStaphylococcus.B. anthraciscauses anthrax,B. cereusmay cause opportunistic infections of the gastrointestinal tract, andS.aureusstrains can cause a wide range of infections an... | https://openstax.org/books/microbiology/pages/4-summary |
Mycoplasmaspp. are very small,pleomorphiclow G+C gram-positive bacteria that lack cell walls.M. pneumoniaecauses atypical pneumonia. | https://openstax.org/books/microbiology/pages/4-summary |
Deeply branching bacteriaare phylogenetically the most ancient forms of life, being the closest to the last universal common ancestor. | https://openstax.org/books/microbiology/pages/4-summary |
Deeply branching bacteria include many species that thrive in extreme environments that are thought to resemble conditions on earth billions of years ago | https://openstax.org/books/microbiology/pages/4-summary |
Deeply branching bacteria are important for our understanding of evolution; some of them are used in industry | https://openstax.org/books/microbiology/pages/4-summary |
Archaeaare unicellular, prokaryotic microorganisms that differ from bacteria in their genetics, biochemistry, and ecology. | https://openstax.org/books/microbiology/pages/4-summary |
Some archaea are extremophiles, living in environments with extremely high or low temperatures, or extreme salinity. | https://openstax.org/books/microbiology/pages/4-summary |
Only archaea are known to produce methane. Methane-producing archaea are calledmethanogens. | https://openstax.org/books/microbiology/pages/4-summary |
Halophilic archaea prefer a concentration of salt close to saturation and perform photosynthesis using bacteriorhodopsin. | https://openstax.org/books/microbiology/pages/4-summary |
Some archaea, based on fossil evidence, are among the oldest organisms on earth. | https://openstax.org/books/microbiology/pages/4-summary |
Archaea do not live in great numbers in human microbiomes and are not known to cause disease. | https://openstax.org/books/microbiology/pages/4-summary |
Protistsare a diverse,polyphyleticgroup of eukaryotic organisms. | https://openstax.org/books/microbiology/pages/5-summary |
Protists may be unicellular or multicellular. They vary in how they get their nutrition, morphology, method of locomotion, and mode of reproduction. | https://openstax.org/books/microbiology/pages/5-summary |
Important structures of protists includecontractile vacuoles, cilia, flagella,pellicles, and pseudopodia; some lack organelles such as mitochondria. | https://openstax.org/books/microbiology/pages/5-summary |
Taxonomy of protists is changing rapidly as relationships are reassessed using newer techniques. | https://openstax.org/books/microbiology/pages/5-summary |
The protists include important pathogens and parasites. | https://openstax.org/books/microbiology/pages/5-summary |
Helminth parasites are included within the study of microbiology because they are often identified by looking for microscopic eggs and larvae. | https://openstax.org/books/microbiology/pages/5-summary |
The two major groups of helminth parasites are the roundworms (Nematoda) and the flatworms (Platyhelminthes). | https://openstax.org/books/microbiology/pages/5-summary |
Nematodes are common intestinal parasites often transmitted through undercooked foods, although they are also found in other environments. | https://openstax.org/books/microbiology/pages/5-summary |
Platyhelminths includetapewormsandflukes, which are often transmitted through undercooked meat. | https://openstax.org/books/microbiology/pages/5-summary |
The fungi include diverse saprotrophic eukaryotic organisms with chitin cell walls | https://openstax.org/books/microbiology/pages/5-summary |
Fungi can be unicellular or multicellular; some (like yeast) and fungal spores are microscopic, whereas some are large and conspicuous | https://openstax.org/books/microbiology/pages/5-summary |
Reproductive types are important in distinguishing fungal groups | https://openstax.org/books/microbiology/pages/5-summary |
Medically important species exist in the four fungal groups Zygomycota, Ascomycota, Basidiomycota, and Microsporidia | https://openstax.org/books/microbiology/pages/5-summary |
Members of Zygomycota, Ascomycota, and Basidiomycota produce deadly toxins | https://openstax.org/books/microbiology/pages/5-summary |
Important differences in fungal cells, such as ergosterols in fungal membranes, can be targets for antifungal medications, but similarities between human and fungal cells make it difficult to find targets for medications and these medications often have toxic adverse effects | https://openstax.org/books/microbiology/pages/5-summary |
Algae are a diverse group of photosynthetic eukaryotic protists | https://openstax.org/books/microbiology/pages/5-summary |
Algae may be unicellular or multicellular | https://openstax.org/books/microbiology/pages/5-summary |
Large, multicellular algae are called seaweeds but are not plants and lack plant-like tissues and organs | https://openstax.org/books/microbiology/pages/5-summary |
Although algae have little pathogenicity, they may be associated with toxicalgal bloomsthat can and aquatic wildlife and contaminate seafood with toxins that cause paralysis | https://openstax.org/books/microbiology/pages/5-summary |
Algae are important for producingagar, which is used as a solidifying agent in microbiological media, andcarrageenan, which is used as a solidifying agent | https://openstax.org/books/microbiology/pages/5-summary |
Lichensare a symbiotic association between a fungus and an algae or a cyanobacterium | https://openstax.org/books/microbiology/pages/5-summary |
The symbiotic association found in lichens is currently considered to be a controlledparasitism, in which the fungus benefits and the algae or cyanobacterium is harmed | https://openstax.org/books/microbiology/pages/5-summary |
Lichens are slow growing and can live for centuries in a variety of habitats | https://openstax.org/books/microbiology/pages/5-summary |
Lichens are environmentally important, helping to create soil, providing food, and acting as indicators of air pollution | https://openstax.org/books/microbiology/pages/5-summary |
Viruses are generally ultramicroscopic, typically from 20 nm to 900 nm in length. Some large viruses have been found. | https://openstax.org/books/microbiology/pages/6-summary |
Virionsare acellular and consist of a nucleic acid, DNA or RNA, but not both, surrounded by a proteincapsid. There may also be a phospholipid membrane surrounding the capsid. | https://openstax.org/books/microbiology/pages/6-summary |
Viruses are obligate intracellular parasites. | https://openstax.org/books/microbiology/pages/6-summary |
Viruses are known to infect various types of cells found in plants, animals, fungi, protists, bacteria, and archaea. Viruses typically have limitedhost rangesand infect specific cell types. | https://openstax.org/books/microbiology/pages/6-summary |
Viruses may havehelical,polyhedral,orcomplexshapes. | https://openstax.org/books/microbiology/pages/6-summary |
Classification of viruses is based on morphology, type of nucleic acid, host range, cell specificity, and enzymes carried within the virion. | https://openstax.org/books/microbiology/pages/6-summary |
Like other diseases, viral diseases are classified using ICD codes. | https://openstax.org/books/microbiology/pages/6-summary |
Many viruses target specific hosts or tissues. Some may have more than one host. | https://openstax.org/books/microbiology/pages/6-summary |
Many viruses follow several stages to infect host cells. These stages includeattachment, penetration, uncoating, biosynthesis, maturation,andrelease. | https://openstax.org/books/microbiology/pages/6-summary |
Bacteriophages have alyticorlysogeniccycle. The lytic cycle leads to the death of the host, whereas the lysogenic cycle leads to integration of phage into the host genome. | https://openstax.org/books/microbiology/pages/6-summary |
Bacteriophages inject DNA into the host cell, whereas animal viruses enter by endocytosis or membrane fusion. | https://openstax.org/books/microbiology/pages/6-summary |
Animal viruses can undergolatency, similar to lysogeny for a bacteriophage. | https://openstax.org/books/microbiology/pages/6-summary |
The majority of plant viruses are positive-strand ssRNA and can undergo latency, chronic, or lytic infection, as observed for animal viruses. | https://openstax.org/books/microbiology/pages/6-summary |
The growth curve of bacteriophage populations is aone-step multiplication curveand not a sigmoidal curve, as compared to the bacterial growth curve. | https://openstax.org/books/microbiology/pages/6-summary |
Bacteriophages transfer genetic information between hosts using eithergeneralizedorspecialized transduction. | https://openstax.org/books/microbiology/pages/6-summary |
Viral cultivation requires the presence of some form of host cell (whole organism, embryo, or cell culture). | https://openstax.org/books/microbiology/pages/6-summary |
Viruses can be isolated from samples by filtration. | https://openstax.org/books/microbiology/pages/6-summary |
Viral filtrate is a rich source of released virions. | https://openstax.org/books/microbiology/pages/6-summary |
Bacteriophages are detected by presence of clearplaqueson bacterial lawn. | https://openstax.org/books/microbiology/pages/6-summary |
Animal and plant viruses are detected bycytopathic effects, molecular techniques (PCR, RT-PCR), enzyme immunoassays, and serological assays (hemagglutination assay, hemagglutination inhibition assay). | https://openstax.org/books/microbiology/pages/6-summary |
Other acellular agents such asviroids,virusoids, andprionsalso cause diseases. Viroids consist of small, naked ssRNAs that cause diseases in plants. Virusoids are ssRNAs that require other helper viruses to establish an infection. Prions are proteinaceous infectious particles that causetransmissible spongiform encephal... | https://openstax.org/books/microbiology/pages/6-summary |
Prions are extremely resistant to chemicals, heat, and radiation. | https://openstax.org/books/microbiology/pages/6-summary |
There are no treatments for prion infection. | https://openstax.org/books/microbiology/pages/6-summary |
The most abundant elements in cells are hydrogen, carbon, oxygen, nitrogen, phosphorus, and sulfur. | https://openstax.org/books/microbiology/pages/7-summary |
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