text
stringlengths
2
2.33k
source
stringclasses
724 values
attenuation : weakening of a virus during vaccine development
https://openstax.org/books/biology/pages/21-key-terms
AZT : anti-HIV drug that inhibits the viral enzyme reverse transcriptase
https://openstax.org/books/biology/pages/21-key-terms
back mutation : when a live virus vaccine reverts back to it disease-causing phenotype
https://openstax.org/books/biology/pages/21-key-terms
bacteriophage : virus that infects bacteria
https://openstax.org/books/biology/pages/21-key-terms
budding : method of exit from the cell used in certain animal viruses, where virions leave the cell individually by capturing a piece of the host plasma membrane
https://openstax.org/books/biology/pages/21-key-terms
capsid : protein coating of the viral core
https://openstax.org/books/biology/pages/21-key-terms
capsomere : protein subunit that makes up the capsid
https://openstax.org/books/biology/pages/21-key-terms
cell necrosis : cell death
https://openstax.org/books/biology/pages/21-key-terms
chronic infection : describes when the virus persists in the body for a long period of time
https://openstax.org/books/biology/pages/21-key-terms
cytopathic : causing cell damage
https://openstax.org/books/biology/pages/21-key-terms
envelope : lipid bilayer that envelopes some viruses
https://openstax.org/books/biology/pages/21-key-terms
fusion : method of entry by some enveloped viruses, where the viral envelope fuses with the plasma membrane of the host cell
https://openstax.org/books/biology/pages/21-key-terms
gall : appearance of a plant tumor
https://openstax.org/books/biology/pages/21-key-terms
gene therapy : treatment of genetic disease by adding genes, using viruses to carry the new genes inside the cell
https://openstax.org/books/biology/pages/21-key-terms
group I virus : virus with a dsDNA genome
https://openstax.org/books/biology/pages/21-key-terms
group II virus : virus with a ssDNA genome
https://openstax.org/books/biology/pages/21-key-terms
group III virus : virus with a dsRNA genome
https://openstax.org/books/biology/pages/21-key-terms
group IV virus : virus with a ssRNA genome with positive polarity
https://openstax.org/books/biology/pages/21-key-terms
group V virus : virus with a ssRNA genome with negative polarity
https://openstax.org/books/biology/pages/21-key-terms
group VI virus : virus with a ssRNA genomes converted into dsDNA by reverse transcriptase
https://openstax.org/books/biology/pages/21-key-terms
group VII virus : virus with a single-stranded mRNA converted into dsDNA for genome replication
https://openstax.org/books/biology/pages/21-key-terms
horizontal transmission : transmission of a disease between unrelated individuals
https://openstax.org/books/biology/pages/21-key-terms
hyperplasia : abnormally high cell growth and division
https://openstax.org/books/biology/pages/21-key-terms
hypoplasia : abnormally low cell growth and division
https://openstax.org/books/biology/pages/21-key-terms
intermittent symptom : symptom that occurs periodically
https://openstax.org/books/biology/pages/21-key-terms
latency : virus that remains in the body for a long period of time but only causes intermittent symptoms
https://openstax.org/books/biology/pages/21-key-terms
lysis : bursting of a cell
https://openstax.org/books/biology/pages/21-key-terms
lysogenic cycle : type of virus replication in which the viral genome is incorporated into the genome of the host cell
https://openstax.org/books/biology/pages/21-key-terms
lytic cycle : type of virus replication in which virions are released through lysis, or bursting, of the cell
https://openstax.org/books/biology/pages/21-key-terms
matrix protein : envelope protein that stabilizes the envelope and often plays a role in the assembly of progeny virions
https://openstax.org/books/biology/pages/21-key-terms
negative polarity : ssRNA viruses with genomes complimentary to their mRNA
https://openstax.org/books/biology/pages/21-key-terms
oncogenic virus : virus that has the ability to cause cancer
https://openstax.org/books/biology/pages/21-key-terms
oncolytic virus : virus engineered to specifically infect and kill cancer cells
https://openstax.org/books/biology/pages/21-key-terms
pathogen : agent with the ability to cause disease
https://openstax.org/books/biology/pages/21-key-terms
permissive : cell type that is able to support productive replication of a virus
https://openstax.org/books/biology/pages/21-key-terms
phage therapy : treatment of bacterial diseases using bacteriophages specific to a particular bacterium
https://openstax.org/books/biology/pages/21-key-terms
positive polarity : ssRNA virus with a genome that contains the same base sequences and codons found in their mRNA
https://openstax.org/books/biology/pages/21-key-terms
prion : infectious particle that consists of proteins that replicate without DNA or RNA
https://openstax.org/books/biology/pages/21-key-terms
productive : viral infection that leads to the production of new virions
https://openstax.org/books/biology/pages/21-key-terms
prophage : phage DNA that is incorporated into the host cell genome
https://openstax.org/books/biology/pages/21-key-terms
PrPc : normal prion protein
https://openstax.org/books/biology/pages/21-key-terms
PrPsc : infectious form of a prion protein
https://openstax.org/books/biology/pages/21-key-terms
replicative intermediate : dsRNA intermediate made in the process of copying genomic RNA
https://openstax.org/books/biology/pages/21-key-terms
reverse transcriptase : enzyme found in Baltimore groups VI and VII that converts single-stranded RNA into double-stranded DNA
https://openstax.org/books/biology/pages/21-key-terms
vaccine : weakened solution of virus components, viruses, or other agents that produce an immune response
https://openstax.org/books/biology/pages/21-key-terms
vertical transmission : transmission of disease from parent to offspring
https://openstax.org/books/biology/pages/21-key-terms
viral receptor : glycoprotein used to attach a virus to host cells via molecules on the cell
https://openstax.org/books/biology/pages/21-key-terms
virion : individual virus particle outside a host cell
https://openstax.org/books/biology/pages/21-key-terms
viroid : plant pathogen that produces only a single, specific RNA
https://openstax.org/books/biology/pages/21-key-terms
virus core : contains the virus genome
https://openstax.org/books/biology/pages/21-key-terms
Prokaryotes existed for billions of years before plants and animals appeared. Hot springs and hydrothermal vents may have been the environments in which life began. Microbial mats are thought to represent the earliest forms of life on Earth, and there is fossil evidence of their presence about 3.5 billion years ago. A microbial mat is a multi-layered sheet of prokaryotes that grows at interfaces between different types of material, mostly on moist surfaces. During the first 2 billion years, the atmosphere was anoxic and only anaerobic organisms were able to live. Cyanobacteria evolved from early phototrophs and began the oxygenation of the atmosphere. The increase in oxygen concentration allowed the evolution of other life forms. Fossilized microbial mats are called stromatolites and consist of laminated organo-sedimentary structures formed by precipitation of minerals by prokaryotes. They represent the earliest fossil record of life on Earth.
https://openstax.org/books/biology/pages/22-chapter-summary
Bacteria and archaea grow in virtually every environment. Those that survive under extreme conditions are called extremophiles (extreme lovers). Some prokaryotes cannot grow in a laboratory setting, but they are not dead. They are in the viable-but-non-culturable (VBNC) state. The VBNC state occurs when prokaryotes enter a dormant state in response to environmental stressors. Most prokaryotes are social and prefer to live in communities where interactions take place. A biofilm is a microbial community held together in a gummy-textured matrix.
https://openstax.org/books/biology/pages/22-chapter-summary
Prokaryotes (domains Archaea and Bacteria) are single-celled organisms lacking a nucleus. They have a single piece of circular DNA in the nucleoid area of the cell. Most prokaryotes have a cell wall that lies outside the boundary of the plasma membrane. Some prokaryotes may have additional structures such as a capsule, flagella, and pili. Bacteria and Archaea differ in the lipid composition of their cell membranes and the characteristics of the cell wall. In archaeal membranes, phytanyl units, rather than fatty acids, are linked to glycerol. Some archaeal membranes are lipid monolayers instead of bilayers.
https://openstax.org/books/biology/pages/22-chapter-summary
The cell wall is located outside the cell membrane and prevents osmotic lysis. The chemical composition of cell walls varies between species. Bacterial cell walls contain peptidoglycan. Archaean cell walls do not have peptidoglycan, but they may have pseudopeptidoglycan, polysaccharides, glycoproteins, or protein-based cell walls. Bacteria can be divided into two major groups: Gram positive and Gram negative, based on the Gram stain reaction. Gram-positive organisms have a thick cell wall, together with teichoic acids. Gram-negative organisms have a thin cell wall and an outer envelope containing lipopolysaccharides and lipoproteins.
https://openstax.org/books/biology/pages/22-chapter-summary
Prokaryotes are the most metabolically diverse organisms; they flourish in many different environments with various carbon energy and carbon sources, variable temperature, pH, pressure, and water availability. Nutrients required in large amounts are called macronutrients, whereas those required in trace amounts are called micronutrients or trace elements. Macronutrients include C, H, O, N, P, S, K, Mg, Ca, and Na. In addition to these macronutrients, prokaryotes require various metallic elements for growth and enzyme function. Prokaryotes use different sources of energy to assemble macromolecules from smaller molecules. Phototrophs obtain their energy from sunlight, whereas chemotrophs obtain energy from chemical compounds.
https://openstax.org/books/biology/pages/22-chapter-summary
Prokaryotes play roles in the carbon and nitrogen cycles. Carbon is returned to the atmosphere by the respiration of animals and other chemoorganotrophic organisms. Consumers use organic compounds generated by producers and release carbon dioxide into the atmosphere. The most important contributor of carbon dioxide to the atmosphere is microbial decomposition of dead material. Nitrogen is recycled in nature from organic compounds to ammonia, ammonium ions, nitrite, nitrate, and nitrogen gas. Gaseous nitrogen is transformed into ammonia through nitrogen fixation. Ammonia is anaerobically catabolized by some prokaryotes, yielding N2as the final product. Nitrification is the conversion of ammonium into nitrite. Nitrification in soils is carried out by bacteria. Denitrification is also performed by bacteria and transforms nitrate from soils into gaseous nitrogen compounds, such as N2O, NO, and N2.
https://openstax.org/books/biology/pages/22-chapter-summary
Devastating diseases and plagues have been among us since early times. There are records about microbial diseases as far back as 3000 B.C. Infectious diseases remain among the leading causes of death worldwide. Emerging diseases are those rapidly increasing in incidence or geographic range. They can be new or re-emerging diseases (previously under control). Many emerging diseases affecting humans, such as brucellosis, are zoonoses. The WHO has identified a group of diseases whose re-emergence should be monitored: Those caused by bacteria include bubonic plague, diphtheria, and cholera.
https://openstax.org/books/biology/pages/22-chapter-summary
Biofilms are considered responsible for diseases such as bacterial infections in patients with cystic fibrosis, Legionnaires’ disease, and otitis media. They produce dental plaque; colonize catheters, prostheses, transcutaneous, and orthopedic devices; and infect contact lenses, open wounds, and burned tissue. Biofilms also produce foodborne diseases because they colonize the surfaces of food and food-processing equipment. Biofilms are resistant to most of the methods used to control microbial growth. The excessive use of antibiotics has resulted in a major global problem, since resistant forms of bacteria have been selected over time. A very dangerous strain, methicillin-resistantStaphylococcus aureus(MRSA), has wreaked havoc recently. Foodborne diseases result from the consumption of contaminated food, pathogenic bacteria, viruses, or parasites that contaminate food.
https://openstax.org/books/biology/pages/22-chapter-summary
Pathogens are only a small percentage of all prokaryotes. In fact, our life would not be possible without prokaryotes. Nitrogen is usually the most limiting element in terrestrial ecosystems; atmospheric nitrogen, the largest pool of available nitrogen, is unavailable to eukaryotes. Nitrogen can be “fixed,” or converted into ammonia (NH3) either biologically or abiotically. Biological nitrogen fixation (BNF) is exclusively carried out by prokaryotes. After photosynthesis, BNF is the second most important biological process on Earth. The most important source of BNF is the symbiotic interaction between soil bacteria and legume plants.
https://openstax.org/books/biology/pages/22-chapter-summary
Microbial bioremediation is the use of microbial metabolism to remove pollutants. Bioremediation has been used to remove agricultural chemicals that leach from soil into groundwater and the subsurface. Toxic metals and oxides, such as selenium and arsenic compounds, can also be removed by bioremediation. Probably one of the most useful and interesting examples of the use of prokaryotes for bioremediation purposes is the cleanup of oil spills.
https://openstax.org/books/biology/pages/22-chapter-summary
Human life is only possible due to the action of microbes, both those in the environment and those species that call us home. Internally, they help us digest our food, produce crucial nutrients for us, protect us from pathogenic microbes, and help train our immune systems to function correctly.
https://openstax.org/books/biology/pages/22-chapter-summary
acidophile : organism with optimal growth pH of three or below
https://openstax.org/books/biology/pages/22-key-terms
alkaliphile : organism with optimal growth pH of nine or above
https://openstax.org/books/biology/pages/22-key-terms
ammonification : process by which ammonia is released during the decomposition of nitrogen-containing organic compounds
https://openstax.org/books/biology/pages/22-key-terms
anaerobic : refers to organisms that grow without oxygen
https://openstax.org/books/biology/pages/22-key-terms
anoxic : without oxygen
https://openstax.org/books/biology/pages/22-key-terms
antibiotic : biological substance that, in low concentration, is antagonistic to the growth of prokaryotes
https://openstax.org/books/biology/pages/22-key-terms
biofilm : a microbial community growing together on a surface, often held together with a gummy matrix
https://openstax.org/books/biology/pages/22-key-terms
biological nitrogen fixation : conversion of atmospheric nitrogen into ammonia exclusively carried out by prokaryotes
https://openstax.org/books/biology/pages/22-key-terms
bioremediation : use of microbial metabolism to remove pollutants
https://openstax.org/books/biology/pages/22-key-terms
biotechnology : any technological application that uses living organisms, biological systems, or their derivatives to produce or modify other products
https://openstax.org/books/biology/pages/22-key-terms
Black Death : devastating pandemic that is believed to have been an outbreak of bubonic plague caused by the bacteriumYersinia pestis
https://openstax.org/books/biology/pages/22-key-terms
botulism : disease produced by the toxin of the anaerobic bacteriumClostridium botulinum
https://openstax.org/books/biology/pages/22-key-terms
CA-MRSA : MRSA acquired in the community rather than in a hospital setting
https://openstax.org/books/biology/pages/22-key-terms
capsule : external structure that enables a prokaryote to attach to surfaces and protects it from dehydration
https://openstax.org/books/biology/pages/22-key-terms
chemotroph : organism that obtains energy from chemical compounds
https://openstax.org/books/biology/pages/22-key-terms
conjugation : process by which prokaryotes move DNA from one individual to another using a pilus
https://openstax.org/books/biology/pages/22-key-terms
cyanobacteria : bacteria that evolved from early phototrophs and oxygenated the atmosphere; also known as blue-green algae
https://openstax.org/books/biology/pages/22-key-terms
decomposer : organism that carries out the decomposition of dead organisms
https://openstax.org/books/biology/pages/22-key-terms
denitrification : transformation of nitrate from soil to gaseous nitrogen compounds such as N2O, NO and N2
https://openstax.org/books/biology/pages/22-key-terms
emerging disease : disease making an initial appearance in a population or that is increasing in incidence or geographic range
https://openstax.org/books/biology/pages/22-key-terms
endemic disease : disease that is constantly present, usually at low incidence, in a population
https://openstax.org/books/biology/pages/22-key-terms
epidemic : disease that occurs in an unusually high number of individuals in a population at the same time
https://openstax.org/books/biology/pages/22-key-terms
extremophile : organism that grows under extreme or harsh conditions
https://openstax.org/books/biology/pages/22-key-terms
foodborne disease : any illness resulting from the consumption of contaminated food, or of the pathogenic bacteria, viruses, or other parasites that contaminate food
https://openstax.org/books/biology/pages/22-key-terms
Gram negative : bacterium whose cell wall contains little peptidoglycan but has an outer membrane
https://openstax.org/books/biology/pages/22-key-terms
Gram positive : bacterium that contains mainly peptidoglycan in its cell walls
https://openstax.org/books/biology/pages/22-key-terms
halophile : organism that require a salt concentration of at least 0.2 M
https://openstax.org/books/biology/pages/22-key-terms
hydrothermal vent : fissure in Earth’s surface that releases geothermally heated water
https://openstax.org/books/biology/pages/22-key-terms
hyperthermophile : organism that grows at temperatures between 80–122 °C
https://openstax.org/books/biology/pages/22-key-terms
microbial mat : multi-layered sheet of prokaryotes that may include bacteria and archaea
https://openstax.org/books/biology/pages/22-key-terms
MRSA : (methicillin-resistantStaphylococcus aureus) very dangerousStaphylococcusaureusstrain resistant to multiple antibiotics
https://openstax.org/books/biology/pages/22-key-terms
nitrification : conversion of ammonium into nitrite and nitrate in soils
https://openstax.org/books/biology/pages/22-key-terms
nitrogen fixation : process by which gaseous nitrogen is transformed, or “fixed” into more readily available forms such as ammonia
https://openstax.org/books/biology/pages/22-key-terms
nodule : novel structure on the roots of certain plants (legumes) that results from the symbiotic interaction between the plant and soil bacteria, is the site of nitrogen fixation
https://openstax.org/books/biology/pages/22-key-terms
nutrient : essential substances for growth, such as carbon and nitrogen
https://openstax.org/books/biology/pages/22-key-terms
osmophile : organism that grows in a high sugar concentration
https://openstax.org/books/biology/pages/22-key-terms
pandemic : widespread, usually worldwide, epidemic disease
https://openstax.org/books/biology/pages/22-key-terms
peptidoglycan : material composed of polysaccharide chains cross-linked to unusual peptides
https://openstax.org/books/biology/pages/22-key-terms
phototroph : organism that is able to make its own food by converting solar energy to chemical energy
https://openstax.org/books/biology/pages/22-key-terms