Microbiology Exam 1 Flashcards
the study of organisms and agents too small to be seen clearly by the unaided eye
microbiology
What do microbes in our lives do?
decompose organic waste, generate oxygen by photosynthesis, produce chemical and fermented products
Knowledge of microorganisms allows humans to:
prevent food spoilage and disease, and understand causes and transmission of disease to prevent epidemics
Who established the system of scientific nomenclature?
Carolus Linnaeus
What year did Carolus Linnaeus establish the system of scientific nomenclature?
1735
What is scientific nomenclature?
Each organism has two names: the genus and the specific epithet
What does nomenclature look like?
The genus is capitalized and the specific epithet is lowercase
What are some characteristics of bacteria?
they’re prokaryotes, single-celled and have peptidoglycan cell walls
How do bacteria divide?
by binary fission
What are some characteristics of archaea?
They’re prokaryotes, lack peptidoglycan cell walls and often live in extreme environments
Examples of archaea?
Methanogens, extreme halophiles and extreme thermophiles
What are some characteristics of fungi?
They’re eukaryotes, have chitin cell walls, and absorb organic chemicals for energy.
What are some characteristics of protozoa?
They’re eukaryotes, they absorb/ingest organic chemicals, and may be motile via pseudopods, cilia, or flagella
How do protozoa live?
They’re free-living or they can be parasitic
What are some characteristics of viruses?
They’re acellular, consist of DNA or RNA core, and their core is surrounded by a protein coat.
What does a viruses’ coat look like?
It may be enclosed in a lipid envelope
How do viruses spread?
They’re replicated only when they are in a living host cell, they’re inert outside living hosts
What are some characteristics of multicellular animal parasites?
they’re eukaryotes, multicellular animals, and not strictly microorganisms
Who was the first person to observe microorganisms under a microscope?
Antony van Leeuwenhoek
living organisms can develop from non living matter
spontaneous generation
what’s interesting about spontaneous generation?
up until the 17th century, it was the primary hypothesis to explain how life arises
What did Francesco Redi prove?
Used decaying meat to disprove spontaneous generation of maggots
What did Pasteur prove?
He disproved spontaneous generation by the famous swan necked flask experiment
What was the Miller-Urey experiment?
It produced amino acids and did not produce protein nor a cell. It did not explain how single cell organisms evolve into multicellular organisms but it does show evidence for a Designer.
the idea that microbes caused disease
germ theory
who was thought to be the father of germ theory?
Pasteur
What did Louis Pasteur DO?
correlated process of wine making and beer making with yeast byproducts
What did Joseph Lister DO?
developed the concept of antiseptic surgery - instruments are heat sterilized and phenol is used afterward to eliminate infection
What did Robert Koch do?
demonstrated the role of microbes in causing disease during his study of ANTHRAX
What are Koch’s Postulates?
- Microbe must be present in every case of the disease but not in healthy animal
- Suspected microbe must be isolated and grown in pure culture
- Same disease must result when pure culture inoculated into healthy host
- same microbe isolated from infected host
the idea of injecting attenuated strains to protect healthy animals or humans from microbial infection was termed
vaccination
Who developed the first vaccine?
Pasteur
What was the first antibiotic?
penicillin
Who discovered the first antibiotic and what year?
Alexander Flemming in 1929
Who discovered DNA?
Rosalind Franklin
Which two people proposed the model of DNA?
Watson and Crick
What are some characteristics of Bacillus anthracis?
It’s gram-positive, endospore forming, and causes animal disease anthrax
What does the disease anthrax do?
infects wild and domesticated herbivorous animals
Who identified anthrax?
Robert Koch
What are the three forms of anthrax?
cutaneous, pulmonary, and gastrointestinal
What percentage of anthrax is cutaneous?
95%
What are some symptoms of cutaneous anthrax?
Black ulcer, spore penetration 2 to 5 days later, rarely fatal
What are some symptoms of pulmonary anthrax?
It begins with cold/flu-like symptoms, respiratory infection, it has a 92% mortality rate but a 45% mortality rate when treated early
What are some symptoms of gastrointestinal anthrax?
Nausea, loss of appetite, bloody diarrhea, and fever, followed by bad stomach pain
Is there a vaccine for Bacillus anthracis?
Yes, but it is not available for the general public
What does treatment for anthrax look like?
antibiotics
any kind of microscope that uses visible light to observe specimens
light microscopy
What are the four types of light microscopy?
- Compound light microscopy
- Darkfield microscopy
- Fluorescence miroscopy
- Confocal microscopy
What is the total magnification equation?
Total Magnification = objective lens x ocular lens
the ability of the lenses to distinguish two points
resolution
shorter wavelengths of light provide _______ resolution
greater
a measure of the light-bending ability of a medium
refractive index
What is immersion oil used for?
to keep light from refracting
What does brightfield illumination look like?
Dark objects are visible against a bright background, light reflected off the specimen does not enter the objective lens
What does darkfield microscopy look like?
light objects are visible against a dark background, only light reflected off the specimen enters the objective lens
What does fluorescence microscopy look like?
Object emits light - objects absorbs light and then emits trapped energy
What does confocal microscopy look like?
cells are stained with fluorochrome dyes, short-wavelength light is used to excite a single plane of a specimen
What are some characteristics of electron microscopy?
Uses magnetic lenses, uses electron beam in place of light, specimen must be stained.
What is transmission electron microscopy used for?
virus and cross sections of cells
what is scanning electron microscopy used for?
visualizes surfaces or surface structures
the internal and external structures of a cell and the microorganism itself are fixed in place
Fixation-Process
What are the two types of bacteriology?
Heat fix and chemical fix
Examples of simple stains
crystal violet, malachite green, safranin, acid fuchsin
examples of differential staining
gram stain, acid-fast, endospore staining, capsule staining
What are some characteristics of mycobacterium tuberculosis
rod shaped actinomycete, infectious agent for tuberculosis, does not accept staining well
Since mycobacterium doesn’t accept simple stains, what do we classify it as?
mycolic acid
what is harsh staining treatment called
acid fast
What percentage of the world is infected with tuberculosis
33%
Tuberculosis Detection?
Skin Test Positive, Blood, Sputum, Chest X-Ray
Symptoms of tuberculosis?
Active infection cough, weight loss, bloody sputum
What group of people is more susceptible to TB?
AIDS victims
What are examples of cell shapes
cocci, rod, vibrio
what is the composition of bacterial glycocalyx
carbohydrate
What are the two types of bacterial glycocalyx
capsule and slime layers
what is the function of glycocalyx
contributes to virulence and stores lots of water thus makes cells resistant to drying
What is the composition of flagella?
protein
What are the three parts of flagella?
basal body, hook, filament
What is the function of flagella?
motility
one flagella located at a pole or end
monotrichous
single flagella at both ends
amphitrichous
tuft of flagella at one or both ends
lophotrichous
flagella around entire surface of bacteria
petritrichous
what is the composition of pili or fimbriae
the protein pilin
what is the function of pili/fimbriae
transfer of genetic material, attachment to surfaces, twitching motility
What is the motility of flagella?
swimming and swarming
what is the motility of pili
twitching
What is the motility of taxis
chemoreceptors, and types of taxis
rigid structure outside plasma membrane
bacterial cell wall
what is the function of the bacterial cell wall
determines cell shape, protects from osmotic lysis and toxic substances, and pathogenicity
what are covalently connected to peptidoglycan or plasma membrane
teichoic acids
what is the function of teichoic acids
maintain/create structure, protection, and binding to host tissues
What does LPS stand for
lipopolysaccharides
What are the three types of LPS?
Lipid A, Core Polysaccharide, O antigen
What does the LPS do
stabilizes outer membrane, attaches to surfaces and biofilm formation, creates a permeability layer, protects bacteria from host immune system, endotoxin
What is in a Gram-Positive Cell Wall
Thick peptidoglycan and teichoic acids
What is in a Gram-Negative Cell Wall
Thin peptidoglycan, outer membrane, and periplasmic space
what is different about the archea cell wall
no peptidoglycan but do stain with gram stain either neg or pros
What key metabolic functions happen at the plasma membrane?
transport, respiration, photosynthesis, synthesis of lipids and cell wall constituents, receptors
what is the function of the cytoskeleton
cell division-tubulin, localize proteins, cell shape
what are the types of inclusion bodies
organic vs. inorganic
what are organic inclusion bodies
glycogen-polymer of glucose which is a source of stored carbon and energy
what are inorganic inclusion bodies
polyphosphate granules
ribosomes are the site of what
protein synthesis
Chromosomal DNA is circular DS DNA containing chromosomal genes
nucleoid
extrachromosomal DNA which contains nonessential genes
Plasmid DNA
what does plasmid dna code for
antibiotic resistance and toxin genes
resistant, dormant bodies formed from vegetative cells during adverse conditions
bacterial endospores
what makes an endospore so resistant?
calcium, acid-soluble DNA-binding proteins.
Characteristics of pseudomonas aeruginosa
gram negative bacterium, ubiquitous, and highly motile
There are three forms of motility for pseudomans aeurginosa
swimming and swarming (flagella), and twitching (pili)
The biofilm for pseudomans helps with
nitrogen cycling and opportunistic pathogens
What are the three steps in biofilm formation
attachment, growth, detachment
Pseudomonas attachment surfaces for abiotic
medical devices, soil, oil
pseudomonas attachment surfaces for biotic
lungs, skin, urinary tract
opportunistic pathogen immunocompromised patients
cancer, aids, cystic fibrosis, burn victims, outer ear
What is the percentage of overall prevelance of p aeruginosa infections in US hospitals per discharges
0.4% (4 per 1000)
P aueroginosa is the ____ most commonly isolated nosocomial pathogen
fourth
pathophysiology stages of p auergo
bacterial attachment and colonization, local infection, bloodstream dissemination and systemic disease
virulence factors of p aurego
proteases, exotoxin A, hemolysins
Treatment for p aeurgo
atibiotics and quorum sensing inhibitors
how do flagellum move
beat rather than act like a propellor
how do cilia move
strokes fluid like an oar
the site of respiration and ATP synthesis
mitochondria
true or false the mitochondria contains its own DNA
TRUE
