Final exam Flashcards
Define microbiology
The scientific study of microscopic organisms
Define microorganism
prokaryotic or eukaryotic cells
Define pathogen
A microorganism that causes disease in a host organism
hooks contribution
Observed the first microorganism
Pasteur’s contribution
Proposed germ theory
Koch’s contribution
Experimentally demonstrated the germ theory
Fleming’s contribution
Developed the first antibiotic
Explain how Koch’s postulates demonstrated the germ theory.
a. Koch observed that the microorganisms were present in animals suffering from the disease but absent in healthy animals which suggests the microorganism is the cause of disease.
b. He then isolated the microorganism to make sure the microorganism was the cause.
c. He injected this isolated microorganism into a healthy animal and if the animal became sick it would indicate that the microorganism is the cause of disease.
Compare and contrast simple and differential staining techniques used to visualize bacteria.
Simple staining the dye is attracted to the bacterial cell, while in differential staining the bye is repelled from the bacterial cell.
Compare and contrast the structure of prokaryotic and eukaryotic cells.
Prokaryotic cell: Smaller, less complex, lack’s nucleus.
Eukaryotic cell: Larger, more complex, has a nucleus.
Bacilli
single rods or a chain
Coccus
single or double spheres
Tetrad
group of 4
Spiral
vibrio (comma shaped) or squiggly lines
Pili
fibers used to attach to surfaces
Flagella
tails coming from the cell, used to move
Capsule
a layer external to the cell wall, used to protect the immune system
Peptidoglycan
Maintains the structural strength of the cell wall.
Periplasmic space
the space between the inner and outer membrane in Gram-negative bacteria.
Outer membrane
surrounds the cell wall in gram-negative bacteria, protects against harsh conditions.
Teichoic acid
aids in maintaining the structure of the cell wall.
Lipopolysaccharide (LPS)
Found in Gram-negative bacteria, provides structure and a barrier to protect the cell from harsh conditions.
Nucleoid
Contains genes and the genetic information
Plasmid
contain antibiotic resistance genes
Microcompartment
protein-bound inclusions for a specific function, Ex: Carboxysomes, photosynthetic cyanobacteria.
Selective media
favors the growth of certain microbes (1 growth)
Enriched media
a media that only lets certain microorganisms grow.
Differential Media
a media that contains specific chemicals to differentiate species that possess or lack a biochemical process
Endospore
small seed produced in the bacteria that preserves genetic information
Explain and identify the 4 phases of a typical bacterial growth curve.
a. Lag phase: organisms are adapting to a new environment.
b. Log phase: organisms are doubling the population every generation.
c. Stationary Phase: Growth rate is equal with death rate.
d. Death phase: loss the ability to reproduce.
11) Be able to use the equation g = 1/µ to determine generation time.
a. During one hour of growth in log phase, the cells have doubled 4 times. Based on this info, what is the generation time for this strain of E. coli?
g=1/u
=1/4
=0.25hrx60min/1hr=15 minutes
Sterilization
removes and kills bacteria. Ex: filtration, dry heat, chemical sterilant.
Disinfection
Kills bacteria on inanimate objects. Ex: Bleach, alcohol, ultra-violet light
Antiseptics
slows down the growth of microorganisms. Ex: hydrogen peroxide, alcohol.
Antisepsis
Prevents the growth of bacteria. Ex: hydrogen peroxide, alcohol
Disinfectants
Kills bacteria on inanimate objects. Ex: Bleach, alcohol, ultra-violet light
Provide 3 examples of chemicals used in a medical setting for antisepsis and disinfection.
a. Alcohol
b. Hydrogen peroxide
c. formaldehyde
Provide 3 examples of physical methods used to sterilize or sanitize in a medical setting and in the food industry.
a. heat
b. filtration
c. radiation
Compare and contrast aerobic respiration, anaerobic respiration, and fermentation in bacteria.
a. Aerobic respiration takes place in the cytoplasm and mitochondria and grows with oxygen.
b. Anaerobic takes place only in the cytoplasm and grows without oxygen.
c. Fermentation belongs to anerobic respiration, grows with oxygen.
Biofilm
Microbes that form a protective adhesive that attaches to a surface.
Mesophile
grows between 20-45 degrees C
Thermophile
grows at temperatures above 25-40 degrees C.
Obligate aerobe
must grow in oxygen (cellular respiration)
Facultative anaerobe
can grow with or without oxygen (cellular respiration)
Obligate anaerobe
grows WITHOUT oxygen (fermentative type)
Microaerophile
grows in oxygen concentrations of 2-10% (oxidative metabolic gearing)
Aerotolerant
can tolerate oxygen, but they do not require oxygen. (fermentative type)
Explain what is happening with the lac operon with and without lactose in the environment.
a. Without Lactose: the lack repressor binds tightly to the operator, preventing transcription by RNA polymerase to follow through. blocking the road.
b. With Lactose: changes the shape of the lack repressor just enough that the part responsible for binding no longer has the shape to bind the oppressor (losing the ability to bind DNA). Thus, allowing a clear path for RNA polymerase to transcribe with. Roads are clear.
Compare and contrast the DNA genome of a bacterium versus a eukaryotic cell.
DNA genome of a bacterium: has a single circular DNA molecule, small size, lacks a nucleus.
Eukaryotic cell: has multiple DNA molecules, large size, includes a nucleus.
Compare and contrast the three types of horizontal gene transfer in bacteria (transformation, conjugation, and transduction).
Transformation is the uptake of free DNA from the environment. The donor cell is dead, releasing DNA. The donor can be a different species of bacteria.
Conjugation is the transfer of DNA from one live donor bacteria to a living recipient bacteria. Requires cell-to-cell contact. Donor and recipient can be different species.
Transduction is the transfer of a few donors bacterial genes to a recipient bacteria by the action of a bacteriophage. Donor bacteria, recipient bacteria, virus. The donor and recipient must be the same species.
Mutualism
reaction between organisms where it benefits both.
Commensalism
Interaction that only benefits from One Direction.
Parasitism
Interaction affects hosts negatively.
Microbiome
Microorganisms in a particular environment
Host
where a pathogen effect.
Pathogen
Organism causing disease in host.
Explain how hyaluronidase contributes to the virulence of Staphylococcus aureus.
it breaks down the hylaluronic acids, causing immune avoidance by evading the host immune system
Identify direct and indirect pathogen transmission types including airborne, vector borne, and foodborne.
Airborne: coughing, sneezing, close contact (indirect)
Vector borne: being bitten by a bug (indirect)
Foodborne: eating contaminated food (direct)
Identify 3 locations within or on the human body that contain microbial life.
a. The skin
b. Respiratory system
c. Blood
Identify 2 locations that lack microbes.
Sterile environments and harsh environments
Be able to list 4 factors that impact whether a human host, upon infection, will progress to a disease state.
a. Health conditions
b. Age
c. Vaccines/immunity status
d. hygiene
Virus
obligate intracellular parasites
Identify two ways that antiviral drugs work.
block cell-binding and disrupting the replication cycle
Explain why viruses are obligate intracellular parasites
They need to infect living cells to replicate.
List and explain the symptoms, diagnosis, treatment, transmission and prevention of influenza.
a. Symptoms: fever, headache, stuffy nose, sore throat, cough.
b. Diagnosis: symptoms and testing.
c. Treatment: Bed rest, fluids, antiviral medication.
d. Transmission: direct contact with infection, cough, sneezing etc.
e. Prevention: clean hands, mask, vaccination.
Identify 2 potential complications of influenza.
a. Ear infections
b. pneumonia
Distinguish between “the flu” and “the common cold” on the basis of a patient’s symptoms.
The common colds symptoms are much milder compared to the flu. The common cold may have a runny or stuffy nose, while the flu can cause a list of symptoms.
Identify 4 common steps that are shared among viruses when infecting a cell for replication.
a. Selective binding
b. Entry
c. Virus reproduction
d. Virus release
Name the bacterial species that cause MRSA, tuberculosis, cholera and some gastric ulcers.
a. MRSA: caused by introducing a MRSA strain into a break in the skin.
b. Tuberculosis: caused by a bacterium, Mycobacterium tuberculosis.
c. Cholera: caused by the intestines by consumption of vibrio cholerae.
d. Gastric ulcers: Caused by bacterium, Helicobacter pylori.
Identify the clinical features of MRSA, tuberculosis, cholera, and gastric ulcers caused by H. pylori.
a. MRSA: Swollen, painful, red areas on the skin that develop into pus-filled abscesses.
b. Tuberculosis: Bloody cough with chest pain.
c. Cholera: Severe diarrhea, muscle cramps, and nausea.
d. Gastric ulcers: Stomach pain, indigestion, nausea, vomiting.
Identify 2 risk factors associated with MRSA.
a. skin-to-skin
b. Sharing towels
Explain how cholera exotoxin induces diarrhea.
A bacterium, vibrio cholerae causes infection. The toxins in this bacterium cause the body to create too much water which causes diarrhea.
Explain how H. pylori uses urease to survive the acidity of the stomach and promote ulcer formation
a. The secreting urease, which breaks urea into carbon dioxide and ammonia. The ammonia neutralizes the stomach acid.
b. The acidic stomach juices damage the exposed tissue, causing a peptic ulcer.
List and explain the four key properties of antimicrobial drugs using antibiotics as an example.
a. Antimicrobial spectrum (narrow or broad)
b. Microbiocidal (kills) versus microbiostatic (inhibits growth)
c. Selective toxicity: ability of the drug to kill or inhibit pathogen growth without damage to the host.
d. Therapeutic dose: concentration of a drug used for clinical treatment.
In your own words, explain how fluoroquinolones, penicillin, cephalosporins, and vancomycin kill bacteria.
f uses replication and repairing
p and c inhibit the formation of peptidoglycan
v targets bacterial cell wall synthesis
Identify three common mechanisms of antibiotic resistance.
a. Two species use different mechanisms to withstand the effects of the same antibiotic.
b. Gain resistance from horizontal gene transfer and mutations.
c. A single species may have resistance to multiple drugs.
Define antibiotic, selective toxicity, and antimicrobial spectrum.
a. Antibiotic: targets bacteria to treat bacterial infections.
b. Antimicrobial: kills microorganisms or stops their growth.
c. Spectrum: organization of microorganisms by classification.
