Exam 1 Flashcards
List the steps of the scientific method.
- Observation and description of a phenomenon or a group of phenomena
- Formulate a hypothesis.
- Performance of properly designed experiments
- Draw conclusions.
List and describe the rules of science.
- Science is guided by natural law-physical and chemical laws govern the state of existence
- Science has to be explained by reference to natural law-no supernatural forces or causes or explanations allowed
- Science is testable against the empirical world-observations must be made in the real world for them to have scientific value
- Science’s conclusions are tentative-all scientific conclusions are subject to further verification
- Science is falsifiable-can be proven to be false
Define Theory
well substantiated explanation of some aspect of the natural world that can incorporate facts, laws, and tested hypotheseses
Define Law
descriptive generalization of how some aspect of the natural world behaves under stated circumstances
Define Fact
observation that has has been repeatedly confirmed and for all practical purposes is accepted as “true”
Define Hypothesis
tentative statement about the natural world leading to deductions that can be tested
How does general society vs. scientists use these terms?
Society ranks them Hypothesis, theory, law, then fact; while scientists rank them fact, hypothesis, law, then theory
Define microbiology
the study of living things too small to be seen with the naked eye (microorganisms)
Define taxonomy
The science of classification
Define Phylogeny
the study of evolutionary history of a group of organisms
Define prokaryotic species
a population of cells with similar characteristics
What are the main differences between a eukaryote and prokaryote?
Prokaryotes have no nucleus and no membrane-bound organelles.
Eukaryotes have a nucleus and membrane-bound organelles.
Why is the study of microbiology important?
To understand how the world around us works and the role of life on Earth; microbes are everywhere
How are all living things alike (structures and characteristics)?
Life is organized, requires energy, maintains equilibrium, reproduces, evolves, and has DNA
How did Aristotle and Linnaeus classify organisms?
Aristotle classified them in 2 groups, plants and animals, and Linnaeus classified them in two kingdoms that branched out
Explain Whittaker’s 5 Kingdom System of Classification. How does Woese’s Three Domain System of Classification relate to Whittaker’s system?
Whittaker divided into the 5 kingdoms of prokaryota/Monera, Protista, Fungi, Plantae, and Animalia
These relate because it shows how all living things can be grouped into smaller divisions more like one another
How were bacteria classified according to the 5 Kingdom System?
They were classified in the prokaryotae/monera kingdom
What was the basis for Woese to classify organisms in the Three Domain System?
Sequenced the 16S portion of the ribosomal RNA to show evolutionary relatedness
What is a ribosome?
Site of protein synthesis that is composed of RNA and proteins
Explain the endosymbiotic therory some lines of evidence which supports the Endosymbiotic Theory.
cells evolved a nuclear membrane; eukaryotic cell organelles evolved from prokaryotic cells living inside of the cell
Chloroplast and Mitochondrial Evidence-they have double membranes,only be produced by division of pre-existing mitochondria and chloroplasts, have their own naked and circular DNA, and the have ribosomes that are 70S in size
Why are ribosomes important in studying phylogeny?
They are in all cells and the sequence is fairly similar so that when it is different the change stands out
Explain/List the rules of scientific (binomial) nomenclature and its importance.
1.Genus is capitalized
2. Second name of species, the specific epithet is not capitalized
3.Always underlined or italicized
4.usually tells you something about the organism
The importance is that one organism has the exact same name regardless of where in the world the person is that is talking about it
Manual used to identify bacterial species.
Bergey’s Manuals (there is 2)
Robert Hooke
Used improved microscope and observed “cells” in cork tissue
Cell Theory
van Leeuwenhoek
Viewed “animalcules” in rainwater and materials he scraped from his teeth
What is spontaneous generation
Belief that life arises from dead tissue or non living matter
Francesco Redi (describe his experiments)
Tried to refute animalcules by taking 6 jars and filling them with decaying meat. Three of them were covered and the other three uncovered. There were maggots on the open jars and non on the closed. The problem people had with his experiment is that they said the animalcules needed air to generate
Spallanzani (describe his experiments)
Boiled nutrients solutions in flasks to kill animalcules. He placed the nutrient broth in a flask, sealed it, and then heated it. Again people said there needed to be air.
Louis Pasteur (describe his experiments)
Repeated Spallanzani’s experiment of boiling nutrient broth but did it instead in a swan neck flask so that air could enter in
What else did Pasteur’s experiment contribute to the study of microbiology?
Showed that microbes are present on non-living matter, microbes can be destroyed by heat, airborne contamination can be obstructed and air itself doesn’t create microbes, these discoveries are the basis for aseptic technique
Fracastoro
Germ Theory first proposed; Microorganisms are the causative agent for disease; people didn’t believe for centuries, believed that disease was due to demons or for punishment
Semmelweis
Hand washing prevented childbirth (childbed) fever; start of applying germ theory to medicine even though they didn’t realize it at the time; ran obstetrical clinics
Lister
Phenol on wounds to reduce infection; bacteria cause surgical wound infections; Listerine
Koch
First to show that bacteria actually caused diseases; created postulates
1. Same pathogen present in every case of disease
2. Pathogen isolated from disease host and growth in pure culture
3. Pathogen from pure culture must cause disease when inoculated into a healthy animal
4. Pathogen isolated from inoculated animal is shown to be the original organism
Chinese Healers (did?)
Powder form of smallpox was blown through a tube into the nose of others with a mild form; called variolation.
Jenner
Developed smallpox vaccine; infected people with cowpox, a much milder form, and they never developed smallpox or cowpox after
Ehrlich
Discovered salvarsan, an arsenic derivative for treatment of syphilis
Flemming
Discovered penicillin, the first antibiotic
Pathology
Study of disease
Etiology
cause of disease
Pathogenesis
manner of disease development
What is the difference between infection and disease?
Infection is an invasion or colonization of body or area of body by pathogenic microbe while disease is a change from a state of health but not necessarily from infection
Compare and contrast normal microbiota (resident) versus transient bacteria.
Normal microbiota is permanent microbes that establish residence but cause no disease under normal conditions; transient is there for several days, weeks, months and then gone
What is microbial antagonism?
Normal microbiota preventing overgrowth of harmful microbes thus protecting host
What is an opportunistic pathogen?
Normally not a problem unless the person has poor health or get to an opening in the body it should not be.
What is synergism?
2 or more organisms working together to cause disease
List an example of and define three types of symbioses between bacteria and their hosts?
- Commensalism-skin microbiota host=us; one organism benefits and the other is unaffected
- Mutualism-gut microbiota; both organisms benefit
- Parasitism-infectious disease; one organism living at the expense of the other
What is the difference between a sign and a symptom? Which one does a doctor use to diagnose a disease?
Signs are objectives while symptoms are subjective. Doctors will use both to diagnose.
What is the difference between communicable and noncommunicable disease and give examples of each.
Communicable spreads from one host to another (Herpes, TB, Chicken pox, measles) while noncommunicable does not spread from host to host (Lymes disease and tetanus)
What is a contagious disease (examples also)?
Contagious is a disease that spreads easily such as chicken pox and measles.
What are the categories used to describe disease occurrence, and how do they differ?
Incidence-number that contract during a period of time
Prevalence-fraction of the population that has the disease at one time
Frequency-how often it is in a population
What is the difference between a sporadic, endemic, epidemic, and pandemic? Give examples of each.
Sporadic-occasional; chicken pox and typhoid fever
Endemic-constantly present in population; cold and cholera in India
Epidemic-many people over a “short” period; cholera in South America and influenza
Pandemic-Epidemic world-wide; HIV/AIDS, new subtype of influenza
What are the four categories used to define the severity and duration of a disease and what are examples of each?
Acute-develops rapidly but lasts short time; influenza
Chronic-develops slowly but lasts a long time; TB, Hep B (if progresses)
Subacute-Develops quick but not as fast as acute; measles
Latent-Causative agent remain inactive for awhile; HHV3-shingles
What is the difference between a local, focal, and systemic infection?
Local infection-contained to a small area
Systemic-spread throughout body by blood or lymph
Focal-enter as local and spread through blood or lymph but then are confined to specific area
What is the difference between a primary, secondary, and subclinical infection?
Primary-acute infection that causes initial illness
Secondary-caused by opportunistic pathogen after primary infection has weakened host defenses
Subclinical-infection that does not cause any noticeable illness
What are three ways of contact transmission? Define a fomite.
Direct-physical contact
Indirect-fomites~nonliving objects
Droplet-microbe spread up to one meter
What are all the sources of infections (reservoirs)? What is a zoonoses (examples)?
Humans, animals, and nonliving; zoonoses are diseases that occur in animals and the infection microbe is transmitted to humans.
What is vehicle transmission? List a few examples.
Transmission via medium
Waterborne, foodborne, airborne
What is a vector? Give examples of vectors.
Animal that carry pathogen; mechanical-passive-fly walks on your food; Biological-active-mosquito and tick bites
What is a healthcare associated infection? Why is it such a problem? How are these infections transmitted? How can they be controlled?
Infection that is acquired in a healthcare facility; 5-15% of patients get one and it has gone up 36% in 20 years; microbes in the environment, compromised host, and chain of transmission (staff, catheter, needles, biofilms
What is a predisposing factor to a disease? Can you give any examples?
A factor that makes a person more susceptible to disease; age, race, weakened immune system, gender, job, lifestyle, nutrition.
Define each interval for the development of a disease.
Incubation period-infection until first symptom/signs
Prodromal period-early, mild symptoms and signs
Period of Illness-acute stage more serious signs
Period of decline-symptoms/signs subside.
Period of Convalescence-body returns to original state
What is an emerging infectious disease? Who is responsible for monitoring EID?
New or changing disease or a disease that is incidence increasing; WHO, CDC, NIH
What are some factors that contribute to EID?
Widespread use of antibiotics and pesticides, global climate change, transportation, ecological changes from war/natural disaster/or population changes, animal control, or failure in public health
What is epidemiology?
Science that studies when and where diseases occur and how they are transmitted in populations
What does an epidemiologist do?
Determines etiology of disease, identifies other factors and patterns concerning people affected, and concerned with various methods for controlling a disease
List/discuss the work of early epidemiologists.
John Snow-mid-1800s and investigated cholera outbreaks in London (coming from water pumps)
Ignaz Semmelweis(1848)-investigated childbirth fever
Leprosy~Generally, describe the disease.
Characterized by nerve damage and skin lesions, especially on cooler parts of the body
Leprosy~List and describe the two forms of leprosy.
Tuberculoid-hair follicles, sweat glands, and nerves destroyed; a few skin lesions discolored, dry, and loses sensitivity/feeling
Lepromatous-more severe form; lesions all over the body; skin of face becomes thick and ringed with lesions; lion-like appearance (nose collapses)
Leprosy~What is the cause of leprosy and how is it transmitted?
Cause is Mycobacterium leprae & M. lepromatosis
Transmitted mainly passed person to person but requires long term contact or nasal discharge, respiratory droplets
Leprosy~How is the organism grown for culture or studies?
Commonly grown on the toe pads of armadillos or nude mice
Rabies~What is the transmission of the disease?
Direct contact (most common)-bite/saliva from rabid animal
Rare(aerosol)- mucous membranes (corneal transplants)
Rabies~What are some symptoms in humans and animals?
Humans-beginning-flu-like symptoms, malaise, fever, or headache; middle-discomfort or paresthesia at the site of the bite/exposure; end-dilirium, insomnia, hallucinations
Animals-beginning-fever/appetite loss; middle-aggression, seizure, eat anything; end-foaming at the mouth, inability to swallow, and drooling
Rabies~What causes?
Virus in Rhabdoviridae family, genus lyssavirus; negative stranded RNA genome and bullet shaped virion
Rabies~What is the treatment (major and minor)?
Washing of hands with soap and water, PEP-postexposure prophylaxis (1 dose immune globulin and 4 doeses rabies vaccine) over a 14 day period
Milwaukee protocol-therapeutic coma
Rabies~What is done for prevention? What are the main reservoirs worldwide? In the United States? NE?
Pre-exposure vaccine, vaccinate pets, enjoy wild animals from afar, avaid dogs in developing countries
Reservoir-worldwide-dog (90%); US- racoon; NE-skunk
Rabies~Where do you find (or not find) the disease?
Hotspot-us eastern seaboard
Not found in Hawaii new Zealand Japan and Europe
Plague~List and describe the three forms of the plague.
Bubonic-large buboes form that infect the lymph nodes and is the most common form
Pneumonic-Infection moves into lungs and is highly contagious
Septicemic-Rarest form and most lethal where people usually die the day they develop symptoms and gave the name the black death
Plague~What causes the plague?
Yersinia pestis-bacteria that is rod-shaped and gram negative with two non-motile flagella
Plague~What is the vector and reservoir?
Vector-rat flea Xenopsylla cheopis
Reservoir-most commonly black rat but also prairie dogs, ground squirrels, rock squirrels, and chipmunks
Plague~How is the plague treated and prevented?
Treated by immediate isolation and after a diagnosis streptomycin or tetracycline is diagnosed.
Prevented by limiting rodent contact, treating domestic animals for fleas, using insect repellants and rodenticides, using preventative drug therapy, and there is a vaccine
Measles~What is the cause of the disease? Reservoir? Transmission route?
Single-stranded, negative sense RNA virus that is enveloped; Reservior is humans; transmission is through human to human (communicable)4 day incubation period with for days after, virus lives outside host for 2 hours and is transmitted through close contact
Measles~List several signs/symptoms of the disease. Severe complications.
Fever-up to 40 °C, cold-like symptoms (runny nose and cough), Koplik’s spots (may or may not be present), and a rash that spears on the face after day 2, starts on face and nech then spreads and lasts about 5-6 days
Complications-1/10 get ear infection; 1/20 pneumonia; 1/1000 encephalitis;1-2/1000 die
Measles~Main form of prevention?
Vaccination-2 doses that is combined with Mumps and Rubella (MMR)
Measles~Worldwide cases (number) before vaccine use? Deaths before vaccine “push”?
Cases-20 million worldwide
Deaths-2.6 million per year
