Download MICROBIOLOGY TO MIDTERM QUESTIONS WITH ANSWERS 2025 and more Exams Nursing in PDF only on Docsity!
WITH ANSWERS 2025
viruses - correct answers "obligate intracellular parasites" - can live and multiply only inside host cell
- small (1/10th size of bacteria)
- causes fatal diseases Bacteria - correct answers large group of one celled mo's. vary in size and shape. ideal 98.6F in moist, dark environment algae - correct answers range from single celled to larger multiple cell most do not produce disease protozoa - correct answers large group of one celled mo's, no rigid cell wall. small # responsible for intestinal infections. Prokaryote - correct answers primitive cells, no internal membrane, no nucleus
- bacteria Girolamo Fracastoro - correct answers - existence of "tiny living particles" that cause "catching" diseases
- spread by direct/indirect contact
- named syphilis in poem Antoni Van Leeuwenhoek - correct answers - discovered bacteria
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- first to "see" microbe
- primitive microscope
- named "animacules"
- saw plaque Edward Jenner - correct answers - concept of immunizations, injected smallpox for cowpox Louis Pasteur - correct answers Father of Immunology
- associated living organisms with disease
- wine industry = pasteurization
- discovered anthrax and cholera, created vaccines for rabies anthrax and cholera John Tyndall - correct answers "tyndallization"
- discovered prolonged heating to destroy bacteria
- heat sensitive/heat stable Ferdinand Cohn - correct answers endospores Joseph Lister - correct answers - airborne microorganisms
- phenols/carbolic acid reduce airborne MO's, used in WWII.
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cytoplasm(Prokaryotic cell) - correct answers - contained within cytoplasmic membrane
- aqueous solution contains water, proteins, carbs, inorganic salts granules (Prokaryotic cell) - correct answers energy reserve plasmids (Prokaryotic cell) - correct answers - extra chromosomal DNA
- resistant to physical and chemical agents + antibiotics (bacteria can grow) Vesicles (Eukaryotic Cell) - correct answers surrounds proteins; occurs in endocytosis/exocytosis lysosomes (Eukaryotic Cell) - correct answers membranous sacs, contain digestive enzymes Characteristics Of Bacteria Cell - correct answers - smallest of the unicellular organisms
- very rapid metabolic rate due to large surface area to volume Gram positive - correct answers blue/purple cell walls, thick layer
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Gram negative - correct answers pink/red cell walls, thin layer Basic cell shapes/sizes - correct answers 1. spheres or cocci
- rods or bacilli
- spirilla or spirochetes binary fission - correct answers each cell divides into two daughter cells 5 growth requirements of bacteria - correct answers temperature, acidity, nutrients, oxygen metabolism, water Bactericidal agents - correct answers kill bacteria (chemical or physical) Bacteriostatic agents - correct answers prevents growth without killing them How to kill bacteria - correct answers physical or chemical means.
- high temp
- strong chemicals (bactericidal, virucidal, fungicidal) Classification of viruses - correct answers - grouped into families but not classified. Defined by:
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Assembly (Life cycle of a virus) - correct answers capsid surrounds nucleic acid Release from host cell (Life cycle of a virus) - correct answers after invading host cell it must be able to release from host cell and replicate elsewhere Viruses require what to survive - correct answers host cell
- cannot generate energy or synthesize nucleic acid and proteins by themselves, so they must rely on a host Transmission of Viruses - correct answers 1. droplets (sneezing)
- direct transfer (touching)
- contaminated food or water
- insects Endogenous diseases - correct answers Caused by microorganisms on/in the body Exogenous diseases - correct answers caused by microorganisms not normally present in/on body. contaminate from outside Toxigenic disease - correct answers exogenous MO's causing disease without entering& multiplying in the body (food poisoning) Bacteriophage - correct answers Viruses that infect bacteria
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Prion - correct answers - infection agent composed of protein causing rare degenerative brain disease called Creutzfeldt- Jacob.
- Not MO's, always fatal. "mad cow" Asepsis - correct answers - prevents contamination by unwanted MO's
- absence of infection/infectious materials eg. cleaning dental chair 4 modes of disease transmission - correct answers 1. Direct contact
- Indirect contact
- Droplet infection
- Airborne infection Routes of entry into the body - correct answers inhalation, ingestion, mucous membranes, breaks in the skin lyophilization - correct answers preserving microbes from a substance by removing the water, rapidly freezing sample, then drying it w/vacuum pump, at very low temperature
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- Radiation 3 groups of bacteria based on temperature - correct answers Thermophiles: warm, 56 Mesophiles: body temp, 37 Psychrophiles: cold, fridge temp 7 Mesophiles - correct answers body temp: 22-45, ideal 37 caries, periodontal disease, TB, bacterial pneumonia, tetanus. Thermophiles - correct answers heat loving: 45-70, ideal 56 compost, "geyser" hot water Psychrophiles - correct answers cold loving: 1-22, ideal 7 fridge food Obligate Aerobes - correct answers grow in presence of oxygen (20%)
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Obligate Anaerobes - correct answers grow in absence of oxygen Facultative Anaerobes - correct answers can live with or without oxygen without: undergoes anaerobic respiration/fermentation + less ATP=less growth Microaerophiles - correct answers can tolerate only low conc. of oxygen (4%) 99% of the bacteria in the mouth are: - correct answers obligate anaerobes or facultative anaerobes 2 groups of bacteria based on acidity - correct answers Acidogenic/Aciduric Ideal: 7 Acidogenic - correct answers Bacteria that produce acids during growth Aciduric - correct answers bacteria that survive and grow in an acidic environment (ph<5.5) Halophilic Bacteria - correct answers sodium chloride (salt) loving bacteria Haloduric Bacteria - correct answers capable of existing (but do not prefer) in a medium containing a high concentration of salt
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Radiation - Ultraviolet Light - correct answers - damages DNA
- mutations will result in cell death
- inability to replicate chromosome
- inability to transcribe mRNA What Is An Antimicrobial? - correct answers term used to designate all the categories of drugs used to treat infections. How Do Antimicrobials Work? - correct answers - interfere with growth and replication of microbes
- damages host cell
- antibacterial, can be added to mouthwash Antibiotics - correct answers - 1950's
- one type of antimicrobial, act on prokaryotic cell
- antibiotics do not harm eukaryotic cells or viruses Sulfonamide - correct answers antibacterial agent, bacteriostatic inhibits growth, does not kill
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CDC (Center for Disease Control) - correct answers creates guidelines & recommendations for infection control in dental settings Resident skin flora - correct answers cannot be removed totally with sx scrub always on skin, MO's colonize and become permanent Transient flora - correct answers source of disease contaminates, does not colonize/remain, can be removed by washing Sterilant - correct answers Destroys all microorganisms including spores High level disinfectant - correct answers Destroys all microorganisms, but not all spores Intermediate-level disinfectant - correct answers Destroys bacteria, fungi and most viruses Low-level disinfectant - correct answers Destroys bacteria, some fungi and some viruses Dental Unit Waterlines: Biofilm and Water Quality - correct answers 1. Discharge air and water for 20-30 secs after each client
- Flush waterlines and faucets for 1-5 mins before using
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causes: handwashing with irritating cleaners or antiseptics, failure to rinse/dry, excessive perspiration, irritation from powder allergic contact dermatitis - correct answers type IV "delayed hypersensitivity" : within 24 - 48 hrs.
- most common reaction to gloves, limited to contact areas hands = red, itchy, with vesicles in the first 24-48 hours, followed by dry skin, fissures and sores Latex allergy - correct answers Type I 'immediate hypersensitivity' symptoms occur within 20minutes. Hives redness burning and itching, respiratory problems, asthma - > anaphylactic bacterial flora: - correct answers normally resides in or on body without causing harm, disease potential Locations of endogenous bacteria: - correct answers skin, mouth, gastrointestinal tract, upper respiratory tract, eyes Locations of endogenous bacteria: skin - correct answers abundance of constant flora. acidity/sebum play a rile in skin microbiota Disruption = infections (athletes foot)
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Locations of endogenous bacteria: mouth - correct answers - normal oral microbiota are on teeth, in saliva and on soft tissues. saliva is mediating factor (flow, viscosity, pH, mineral content) Disruption = caries, perio Locations of endogenous bacteria: gastro tract - correct answers Upper tract: microbial flora fluctuates due to stomach acidity Lower tract: flora increases in numbers (lower intestines) Disruption = E-Coli Locations of endogenous bacteria: upper respiratory tract - correct answers microbes filtered from air as it passes through, transient species trapped on membranes and swallowed Disruption = pneumonia Locations of endogenous bacteria: eyes - correct answers free of complex resident microbiota due to tears Disruption = pink eye Progression of disease depends on: - correct answers 1. Virulence factors of MO's
- Quantity of microbial invaders
- Resistance factors of the host
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endogenous disease - correct answers - caused by MO's normally present in/on body without causing harm causative agents: opportunistic pathogens ex. perio, caries exogenous disease - correct answers - caused by MO's not normally present in/on body, contaminate from outside causative agent: toxigenic ex. common cold, Hep, chicken pox Steps of disease development: (exogenous) - correct answers 1. Source of MO (mouth, carriers)
- Escape of MO from source (aerosols, droplets, etc)
- Spread of MO to new person (direct/indirect, etc)
- Entry of MO into new person (no damage w/o entering)
- Infection (multiplication/survival)
- Damage (develop to harmful level) Stages of infectious disease: - correct answers 1. Incubation Stage
- Prodromal Stage
- Acute Stage
- Convalescent Stage
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Stages of infectious disease: incubation - correct answers from initial entrance to display of 1st symptoms (hours to years) Stages of infectious disease: prodromal - correct answers early symptoms Stages of infectious disease: acute - correct answers very ill, maximum symptoms Stages of infectious disease: convalescent - correct answers recovery phase, infectious agent still present and may spread Pathogenic properties of MO's: - correct answers 1. Enhancement of infection
- Interference with host defenses
- Direct damage to body Pathogenic properties of MO's: Enhancement of infection - correct answers - MO's can multiply, body attempts to counteract
- result of these interactions is either health or disease
- plaque is an example of bacterial attachment to host leading to caries Pathogenic properties of MO's: Interference with host defenses - correct answers many MO's are pathogenic and interfere with host defenses
