09. Microbiology [DEFINITIONS] Flashcards
Microbiology
Microbiology is the study of organisms that are too small and are not visible clearly to the naked eye or un-aided eye when they exist individually.
Photoautotrophs
Photoautotrophs are organisms that use light as a source of energy and carbon dioxide as the source of carbon
Photoheterotrophs
Photoheterotrophs are organisms that use light as a source of energy and organic carbon as their source of carbon
Chemoautotrophs
Chemoautotrophs are organisms that use inorganic chemicals as a source of energy and carbon dioxide (inorganic carbon) as a source of carbon
Chemoheterotrophs
Chemoheterotrophs are organisms that use organic chemicals as a source of energy and organic carbon as their source of carbon
Obligate Aerobes
Obligate aerobes require oxygen for their survival and generate energy by oxidative phosphorylation
Obligate Anaerobes
Obligate anaerobes cannot survive in the presence of oxygen and generate energy by fermentation
Facultative anaerobes
Facultative anaerobes prefer to grow in the presence of oxygen producing energy by oxidative phosphorylation, but they can also grow in anerobic environments using fermentation
Microaerophiles
These microorganisms can grow only in oxygen concentrations lower than those in the air.
Akinete
Thick walled resting spores with stored food
Nitrogenase Enzyme
It is an enzyme which catalyzes nitrogen fixation
Heterocyst
A structure containing a thick wall to protect nitrogenase enzyme from oxygen that could diffuse from neighboring photosynthetic cells and air or water
Mollicutes
Mollicutes are prokaryotes included in the domain bacteria. Mycoplasma and phytoplasma are considered unique due to the absence of cell walls.
Virus
They are neither eukaryotes or prokaryotes and do not show any cellular organization.
Helical Viruses
Helical viruses are long rigid or flexible rods
Icosahedron/ Polyhedral
Icosahedron symmetry (ex: adeno virus)
Complex viruses
Exhibits more than one form of symmetry with additional structures (ex: bacteriophage)
Enveloped viruses
Roughly spherical, capsid covered by envelopes (ex: Herpes simplex virus)
Viroids
Viroids consist only of short piece of naked RNA with no protective layer such as a protein coat.
Prions
Prions are proteinaceous infectious particles which are smaller than viruses.
Sterilization
Sterilization is the process of removal or destruction of all forms of microbial life including endospores
Nutrient Agar (NA)
It is a general medium used to grow bacteria made of peptone, meat extract, sodium chloride, agar and distilled water.
Potato Dextrose Agar (PDA)
General media used to grow fungi and made up of potato, glucose, agar and distilled water.
Pathogen
An organisms or entity (non-living entities such as virus and prions) that is capable of causing disease
Host
Organism within which infected pathogens live on or in and multiply
Pathogenicity
The ability of a pathogen to cause disease in the host by overcoming the defense of a host
Parasite
An organisms or entity living on or in another living organism (host) and obtain nutrients and other resources from the host.
Virulence
Virulence is the degree of pathogenicity of the pathogen
Virulent Factors
Few genes of pathogenic microorganisms express factors which provide them the ability to infect their host and cause disease. Such factors are called virulent factors
Phospholipase
Destroy animal cell membranes
Toxigenicity
Ability of microorganisms to produce biochemical substances known as toxins that disrupt the normal functions of cells.
Neurotoxins
Interfere with normal transmission of nerve impulses (ex: toxins produced by Clostridium tetani)
Enterotoxins
Stimulates cells of the gastrointestinal tract in an abnormal way (ex: toxins produced by Vibrio cholera)
Cytotoxins
Kills host cells by enzymatic attack (ex: toxins produced by Corynebacterium diphtheriae)
Live Attenuated Vaccines
Vaccine contains live pathogens which were deliberately weakened for its pathogenicity. These vaccines mimic an actual infection
Inactivated Vaccines
Pathogenic microorganism is inactivated or killed in the vaccine. Compared to live attenuated vaccines, inactivated killed vaccines often require repeated booster doses.
Subunit Vaccines
Subunit vaccines contain only the antigenic fragments of a pathogen that can induce immunity in the recipient
Bioremediation
Bioremediation is a technology that applies of living organisms to remove, degrade or detoxify pollutants. Bioremediation naturally occurs in the soil.
Nitrification
Nitrification is the process of oxidation of nitrogen in the ammonium ion to produce nitrate.
Denitrification
In the absence of atmospheric oxygen, some microorganism use nitrate and reduces it into N2. This process is called denitrification.
Nitrogen Fixation
The process of conversion of nitrogen gas to ammonia is termed as nitrogen fixation
Mycorrhizae
Mycorrhizae are symbiotic associations between plant roots with fungi
Sedimentation
Filtration
After sedimentation and coagulation, water is filtered by passing through beds of fine sand. Filtration removes protozoan cysts and other microorganisms.
Disinfection
The final step in water treatment.
Food Spoilage
Growth of microorganisms in food changes physical, chemical and biological structures of food and making them unfit for consumption.
Putrefaction
Protein present in the food source is broken down by the proteolytic enzymes secreted by proteolytic microorganisms into amino acids, amines, ammonia and hydrogen sulphate (HS)
Fermentation
Rancidity
Here, the lipids present in the food source are converted into fatty acids and glycerol by enzymes secreted by lipolytic microorganisms
