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147 Cards in this Set
- Front
- Back
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Know the steps in culturing microorganisms.
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A. Inoculation
B. Isolation C. Incubation D. Inspection E. Identification |
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Inoculation
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introduce a tiny sample into nutrient medium (inoculums).
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Isolation
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separating cells.
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Incubation
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inoculated medium is placed in an incubator.
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Inspection
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cultures are examined and evaluated macroscopically.
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Identification
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species is determined.
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What are the general characteristics Prokaryotes
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Do not contain a nucleus or organelles, usually smaller than eukaryotes,
Ex: ALL BACTERIAS. |
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What are the general characteristics Eukaryotes
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Organisms composed of a cell or many cells that have a nucleus and organelles.
Ex: Fungi, Protists, and Helminth worms. |
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Unicellular
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Composed of one cell
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Multi-cellular
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Consisting of many cells
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Free-living
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A lifestyle usually in soil or water, harmless, even beneficial. Some have symbiotic relationship with other organisms
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Parasitic
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Living in or on a host from which nourishment is derived while causing damage. Ex: worms
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Spread plate
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Liquid inoculums is pipette onto the surface of a solid medium and spread around
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Streak plate
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Inoculum is spread over the surface of a solid medium
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Pour plate or loop dilution
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Inoculum is introduced onto a series of liquid media, the poured out into a petri dish
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What is a hockey stick?
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An instrument used to spread inoculums around
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Periplasmic
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Internal flagella located between the cell wall and the cell membrane to create a wriggling motion in spirochetes.
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Peritrichous
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Flagella are randomly placed all over the cell’s surface
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Lophotrichous
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Tufts of flagella at one site
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Amphitrichous
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Flagella at both ends
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Monotrichous
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one flagellum.
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What are the parts of the cell envelope?
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cell wall and cell membrane
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Bacillus
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rod
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coccus
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sphere
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spirillum
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helix/ wavy/ corkscrew
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vibrio
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comma shaped
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Distinguish between gram+ and gram- cells by describing the cell wall and periplasmic space.
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Gram - has wide periplasmic space, thin peptidoglycan layer.
Gram + has narrow periplasmic space, thick peptidoglycan layer |
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Gram -
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has wide periplasmic space, thin peptidoglycan layer.
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Gram +
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has narrow periplasmic space, thick peptidoglycan layer
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Describe rickettsias and name a disease caused by a rickettsia.
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Rickettsias are Gram- intracellular parasite.
Rocky Mountain spotted fever is the disease caused by Rickettsia. |
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Trophozoite
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is feeding stage of protists.
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Cyst
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dormant, resting stage that allows the protozoan to survive adverse situations. [Entamoeba histolytica and Giardia lamblia can be transmitted in this stage.]
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What is a prion?
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Are naked protein molecules. No DNA or RNA, but are capable of causing infections.
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What human diseases do prions cause?
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Transmissible spongiforms-- Bovine spongiform encephalopathy (mad cow disease), Creutzfeldt-Jakob, kuru, fatal familiar insomnia.
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How do they affect the patient?
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destroy neurons (nerve cells) and glial cells.
There is no treatment. Deterioration of the brain, loss of motor coordination, sensory and cognitive abilities precede death. |
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Rate prions resistance to heat, radiation, and other microbial controls.
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Prions are highly resistant to disinfectants and radiation. Very high temperatures and treatment with strong alkaline chemicals can deactivate them.
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Psychrophile
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optimal temp. Is below 25 degrees C and grow at 0 degrees C. rarely pathogenic.
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Mesophile
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have optimal temp. Between 20 degrees C and 40 degrees C. Most human pathogens.
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Thermophile
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grows best at greater than 45 degrees C
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capnophile
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Microaerophile that requires elevated co2 levels
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microaerophile
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microorganism that requires oxygen to survive, but requires environments containing lower levels of oxygen than are present in theatmosphere
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Name in order the stages in the normal bacterial growth curve.
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Lag, log, stationary, death
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Lag phase
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early period, no or slow growth. {New environment}
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Log or Exponential growth phase
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Growth curve increases. {Maximum growth}
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Stationary growth phase
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curve levels off, cells stop growing. {Some growth, some death}
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Death phase
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cell death accelerates to exponential rate as conditions deteriorate.
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What are the components of all viruses?
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capsid, nucleic acid, enzymes
All viruses have a protein shell or capsid that surrounds the nucleic acid (either DNA or RNA). Viruses have either RNA or DNA not both; they are surrounded by a capsid, and have no cell wall. |
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Know the stages and events of the multiplication cycle of an animal virus.
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Adsorption
Penetration/Uncoating Synthesis Assembly Release |
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Adsorption
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attachment to specific receptor sites on the cell membrane. (stick)
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Penetration or uncoating
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the entire virus or just the nucleic acid enters the cell. (Entry into cell)
the viral nucleic acid is released from the capsid |
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Synthesis
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viral components are produced through replication and protein synthesis.
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Assembly
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Virus particles are constructed from the accumulating components. (Put together)
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Release
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assembled viruses are released by budding (exocytosis) or cell lysis
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What elements are present in ALL organic molecules?
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carbon and hydrogen
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What are the products of fermentation?
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carbon dioxide, lactic acid, alcohol (ethanol)
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Alcoholic fermentation
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produces ethanol and carbon dioxide.
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Acidic fermentation
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Pyruvate is reduced to lactic acid and or other acids.
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What is the ultimate electron acceptor in the ETS of cellular respiration?
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oxygen
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What is the effect of streptokinase?
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Enzyme by S. pyogenes that digests blood clots to assist in invasion of wounds
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What is the action of chioramphenicol in microbial control?
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Chloramphenicol binds to ribosomes where proteins are assembled to prevent protein synthesis so proteins can’t be assembled
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Name the 2 halogens most often used in microbial control.
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iodine and chlorine
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Rate the resistance from greatest to least of: enveloped viruses, naked viruses, trophozoites, cysts, bacterial endospores.
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bacterial endospores, cysts, naked viruses, enveloped viruses, trophozoites
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What method is used to produce multiple copies of DNA?
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polymerase chain reaction
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Describe how an adenovirus has been modified for medical purpose.
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attacks and lyses cancer cells
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Characteristic Exotoxin
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Toxicity Minute amounts
Effects Specific to cell type Immune response stimulate antibodies Fever stimulation Usually not Manner of release Secreted by cell Typical sources few gram+, gram- |
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Characteristic Endotoxins
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Toxicity requires high doses
Effects systemic: fever, inflammation Immune response does not stimulate antibodies Fever stimulation YES Manner of release released from cell wall during lysis Typical sources All gram- |
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Know the stages in development of infection and disease.
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Incubation, prodromal, invasion, convalescence
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Incubation stage
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time from initial contact with the infectious agent to onset of symptoms. Ranged from 2-30 days although incubation period of leprosy is several years
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prodromal stage
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time of earliest perception of symptoms, 1-2 days
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invasion stage
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agent multiplies rapidly, shows greatest toxicity, becomes well established in target tissue
1. often includes fever and symptoms specific to the infection. Syndrome- complex of signs and symptoms that identify a certain disease. 2. time varies |
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convalescence stage
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immune response brings healing, and patient regains health and strength
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What are the purposes of pasteurization?
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inactivates viruses, prevents transmission of milk-borne disease by reducing numbers of microbes
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What is the effect of boiling water or steam in biological control?
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They are physical controls (moist heat); main effect is coagulation of proteins. Most processed foods use moist heat.
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Describe the use of ionizing radiation in the sterilization of food?
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Ionizing radiation (gamma rays, X-rays, Cathode rays) used in preserving food: kills bacterial pathogens, insects, and worms. Does not make food radioactive.
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Against which pathogens is hydrogen peroxide effective as a control?
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Effective against bacteria, viruses, fungi, and spores by the action of oxygen that forms hydroxyl free radicals that are highly reactive to cells.
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Why is it effective against anaerobes, especially?
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Produces oxygen that is toxic to anaerobes.
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Morbidity
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# of disease cases
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mortality
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total # of deaths
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prevalence
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% of population with disease
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incidence
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number of new cases over a certain period of time.
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Epidemic
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prevalence greater than expected.
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Pandemic
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spread of epidemic across continents.
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Endemic
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relatively steady frequency over long time.
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Why is aflatoxin so dangerous?
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Highly toxic, causes liver cancer, lethal to livestock.
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Why is it so difficult to develop immunity to the rhinovirus?
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Many exposed knobs on viruses that cause cold so immune system may not have produced antibody for all.
Capsid subunits |
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Why is it so difficult to develop immunity to the orthomyxovirus (influenza)?
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use antigenic drift and antigenic shift to to frustrate the immune system
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What are the agent, vector and effects of Changas disease?
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agent is Trypanosoma cruzi, vectored by the kissing bug. Causes an enlarged heart.
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What is the agent for most stomach ulcers?
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Helicobacter pylori –agent for 90% of stomach and duodenal ulcers and a cofactor in development of a type of stomach cancer.
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How is Giardia lamblia transmitted?
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By cyst stage, may be ingested from environmental water
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What are some characteristics of Candida albicans?
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Candida albicans are opportunistic mycoses, normal flora of 20% of humans, usually endogenous, but can spread in nurseries, through surgery, childbirth, and sexual contact. Infections usually involve mucous of membranes mouth (thrush) and vagina (yeast infections).
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What is the scientific method?
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Process used by scientist to solve problems.
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Hypothesis
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a statement that can be tested by observation or experimentation
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Theory
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Hypothesis that has been repeatedly tested and confirmed by multiple groups of researchers and has been widely accepted
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What are Koch’s Postulates?
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Principle criteria for etiologic studies, i.e., what cause a certain disease
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List the steps to Koch's Postulates
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Find evidence of a particular microbe in every case of a disease.
Isolate that microbe from an infected subject, cultivate it artificially in the lab. Inoculate a susceptible healthy subject with the lab isolate and observe the same resultant disease. Re-isolate the agent from this subject. |
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Virion
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fully formed virus able to establish an infection.
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Viriod
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bit of infectious naked strands of RNA that are pathogens on tomatoes, potatoes, cucumbers, citrus trees, and chrysanthemums.
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Commensal
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ne organism, the commensal, benefits, and the other organism is neither hurt nor helped
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Axenic
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a sterile state as a pure culture. (germ-free)
only one microbe. |
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Pure Culture
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a culture that is composed of one known microorganism. Also Axenic.
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Asepsis
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any practice that prevents the entry of infectious agents into sterile tissues and thus prevents infection.
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Sepsis
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presence of microorganisms or their poisonous products in the bloodstream and other tissues.
growth of microorganisms in blood and tissues. |
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Chemotaxis
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is movement in response to chemical signals toward (positive) or away from (negative).
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Sterile
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absence of life – concept was result of Ferdinand Cohn’s discovery that endospores, resistant structures can survive very high temperatures
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Microbicidals
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agents are designed to kill a specific pathogen
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Microbiostatics
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agents prevent growth temporarily. Useful on the human body because microbicidal agents can damage tissues.
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Sterilization
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destruction or removal of all living organisms and inactivation of viruses.
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Disinfection
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use of a of chemical or physical means to destroy vegetative cells. Usually applied to inanimate objects.
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Degermation –
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reduction of microbial load by mechanical means, e.g. hand washing, use of alcohol wipes.
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Sanitization –
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cleansing to remove debris, microorganisms, toxins to reduce potential for infection or spoilage. Most common are soaps and detergents.
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Lyophilization-
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Freezing and desiccation (drying) to preserve cultures.
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Inoculum -
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Microbes that are introduced into a culture medium to initiate growth
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Pilus -
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hollow, protein structure for transferring nucleic acid between bacteria.
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Fimbriae -
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bristles for attachment.
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disrupts cell membrane.
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Surfactant -
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Compare the vulnerability of young and old microbes to disinfecting agents.
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Age of microbe: Younger, more active is more vulnerable. Older, sedate ones, less so.
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Age of microbe: Younger, more active is more vulnerable. Older, sedate ones, less so.
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Eggs can be contaminated even before the hen lays them.
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What is the effect of an enzyme on rate of reaction?
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Enzymes work as catalysts that increase the rate of a chemical reaction by lowering activation energy but are not part of the reactants or products.
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What is a common method for sterilizing used in the lab?
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Flaming loop
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What are the vector and agent of Lyme disease?
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Borrelia burgdorferi is the agent and is vectored by hard ticks with mice and deer reservoir.
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Evaluate ethylene oxide as a sterilant.
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very effective, but dangerous to use - EXPLOSIVE!!
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Identify the cloning host and genetic donor in recombinant DNA technology.
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Cloning host - bacteria, yeast.
Genetic donor - plant or animal |
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What are some uses of UV radiation in disinfection?
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Non-ionizing radiation: ultraviolet rays (UV), disinfection rather than sterilization; UV lamps are used to disinfect air in hospital rooms, reduce growth of microbes in food processing plants, and purify drinking water, milk, and fruit juices.
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Name some countries in which plague is endemic.
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Africa, S. America, Middle East, Asia, old USSR countries
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Identify the agent of:
Cholera |
Vibrio cholera. Gram- bact.
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Identify the agent of: diphtheria
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Corynebacterium diphtheria. Gram+ bacilli
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Identify the agent of: gas gangrene
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Clostridium –Clostridium perfringens cause gas gangrene.
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Identify the agent of: Hansen's disease (leprosy)
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Mycobacterium leprae.
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Identify the agent of: MRSA (methicillin resistant S.aureas)
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Staphylococci, Staphylococcus aureus.
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Identify the agent of: Rocky Mountain Spotted Fever
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Rickettsia rickettsii.
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Identify the agent of: Scarlet Fever
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Streptococci, Streptococcus pyrogenes.
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Identify the agent of: Toxic Shock Syndrome
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Staphylococci, Staphylococcus
aureus |
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Identify the agent of: Typhoid Fever
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Salmonella typhi.
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Identify the agent of: Walking Pneumonia
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Mycoplasmas, Mycoplasma pneumonia.
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Aerosols
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suspensions of dust or moisture particles that contain pathogens.
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Biological vector
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actively participates in microbe’s life cycle.
communicates the agent by biting, aerosol formation, touch mosquito injects infected saliva into food |
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carrier
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an individual who inconspicuously houses a pathogen and spreads it to others.
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Droplet nuclei
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microscopic pellets of mucous and saliva ejected by a sneeze or cough.
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Fomite
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inanimate object that harbors and transmits pathogens: doorknobs, ect.
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Mechanical vector
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Transport only. Animals can carry the agent on their body surface.
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Nosocomial
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infections not present upon admission to hospital but incurred while being treated.
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Reservoir
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primary habitat for agent
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Source
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the individual or object from which an infection is acquired.
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Zoonosis
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an infection indigenous to animals but transmittable to humans: rabies, plague.
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Are all strains of E. coli pathogenic?
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No E.coli in the lg intestines produces a protein that prevents growth of the pathogens, Salmonella and Shigella
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Describe infestation of humans by flukes
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host is snail, larvae emerge and burrow into humans. Can encyst in the liver
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Why is the opening to the respiratory system the portal of entry for the rhinovirus?
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infection proliferates in temperatures between 33–35 °C (91–95 °F), the temperatures found in the nose.
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