Ch 1: The Microbial World and You Flashcards
Approximately what percent of microbes are pathogenic?
<1%
Intestinal microbes ferment food you can’t digest and produce some of the _______?
B and K vitamins
What species of fungus is responsible for the fermentation of soy sauce?
Aspergillus
Do transient microbiota cause disease? Why or why not?
No.
- unable to compete with residents
- Eliminated by body’s immune system
- Physical or chemical properties that discourage their growth (ex: temp, pH, etc)
By what ratio do microbes outnumber human cells in the body?
10:1
Under what conditions can our normal microbiota cause disease? (3)
- When they escape their normal habitat
- Immunosuppression
- Overgrowth (due to antibiotics)
Who established the system of scientific nomenclature for organisms?
Carolus Linnaeus (Swedish botanist and zoologist)
Theodor Escherich discovered what bacterium? What is its normal habitat?
Escherichia coli
Colon
Break down the name “Staphylococcus aureus”
Staphylo = clustered
Coccus = spherical cells
Aureus = gold-colored colonies
What is the most common way for bacteria to reproduce?
Binary fission
What is the primary component of bacterial cell walls?
Peptidoglycan
True or false. Archaea gain energy from organic and inorganic chemicals as well as photosynthesis.
False. They cannot phosynthesize
What is a halophile?
A microorganism that thrives in high salt concentrations
What are methanogens?
Archaeans that convert hydrogen to methane
What is the primary component of fungi cell walls?
Chitin
Molds and mushrooms are _____ while yeasts are _____
Molds/mushrooms: multicellular
Yeasts: unicellular
Are most fungi molds or yeasts?
Molds
~1% are yeasts
Do protozoans reproduce sexually or asexually?
Either
Are protozoans prokaryotes or eukaryotes?
Eukaryotes
What is the primary component of cell walls in algae?
Cellulose
Who is credited with inventing the first compound microscope in 1595? What was its magnification?
Zacharias Jansen and Hans Lipperhey
3-9x magnification
Robert Hooke’s observation of cork under a primitive compound microscope led to the ________.
Cell theory
1673-1723: _____ was the first person to visualize live microorganisms. He is known as the “father of microbiology”
Anton van Leeuwenhoek
What was the magnification of Leeuwenhoek’s simple microscope?
x300
Describe the “spontaneous generation” theory
Prior to the 1850s, many scientists and philosophers hypothesized that some living organisms could arise from nonliving matter; a “vital force” forms life
(i.e. maggots from decaying corpses, flies from manure)
In 1668, ______ performed the decaying meat experiment to test the spontaneous generation of maggots?
Francesco Redi
In 1861, _____ finally disproved the spontaneous generation theory by designing a flask to let air in but keep microbes out
Louis Pasteur
Describe Pasteurization
Application of heat for a short time to kill pathogens and reduce the number of spoilage bacteria.
Describe the two primary methods of pasteurization
63 ºC for 30 minutes
72 ºC for 16 seconds
Why not boil liquids rather than pasteurize them?
It would evaporate ethanol in alcohol
It would coagulate proteins
In 1876, _____ proved that a bacterium causes anthrax. Proved that specific microbes cause specific diseases
Robert Koch
In 1796, _____ inoculated a person with cowpox virus, who was then protected from smallpox.
Edward Jenner
What is the strict definition of antibiotics? Example?
Agents produced naturally by bacteria and fungi that act against other bacteria
Ex: Penicillin
What is the broad definition of antibiotics? Example?
Drugs used to treat microbial infections
Ex: silver
____ occurs naturally in cinchona tree bark and was the first effective treatment for malaria.
Quinine
In 1910, ______ developed a synthetic arsenic drug, _____, to treat syphilis
Paul Ehrlich
Salvarsan (Ehrlich 606)
In 1928, _____ accidentally discovered the first antibiotic _____.
Alexander Fleming
Penicillin
Microorganisms are responsible for converting what elements into useful forms for plants and animals?
Carbon
Nitrogen
Oxygen
Sulfur
Phosphorus
Bioremediation refers to _____.
Any process that uses organisms or their enzymes to clean up pollutants and toxic wastes
____ produces a crystal protein during sporulation that is toxic to the digestive system of insects, but harmless to plants and animals
Bacillus thuringiensis
What is a biofilm?
A complex aggregation of microorganisms growing on a solid surface
What are some benefits of biofilms?
- Protect mucus membranes from harmful microbes
- Foot for aquatic animals in lakes
- Harnessed for constructive purposes
What are some harmful effects of biofilms?
- Can clog water pipes
- Can colonize medical implants and cause infections
- Increased antibiotic resistance
- Dental plaques can lead to tooth decay
What are some factors that can contribute to emerging infectious diseases (EIDs)?
- Evolutionary changes in existing organisms (increase pathogenicity)
- Changes in weather patterns
- Ecological disasters
- Inappropriate use of antibiotics
- Interactions with animals and livestock
- Urbanization
- War/poverty
- Animal habitat change
- Ineffective or mistaken public health measures
What is H5N1?
Avian influenza A (bird flu)
H5N1 primarily infects _____.
Waterfowl and poultry
Rare in humans (limited and sustained)
What is H1N1?
Swine flu
Influenza A viruses are divided into subtypes based on two surface proteins ______ and ______
Hemagglutinin (H)
Neuraminidase (N)
What are the functions of hemagglutinin in Influenza A? (2)
- Enables the virus to bind cells of the upper respiratory tract containing sialic acid on their membranes
- Allow fusion of the viral envelope with the endosome membrane
What are the functions of neuraminidase in Influenza A?
- Cleaves sialic acid side groups
- Essential for release of progeny virus particles from the surface of infected cells
When a bacteria that is generally harmless finds a route for infection (cut, wound, etc) it is described as _____.
Opportunistic
What is the difference between HA-MRSA and CA-MRSA
HA: healthcare-associated
CA: community-associated
What bacterium causes Tuberculosis?
Mycobacterium tuberculosis
How does the antibiotic isoniazid function?
Blocks peptidoglycan cell wall synthesis
How does the antibiotic rifampin function?
Blocks bacterial DNA polymerase
True or false. M. tuberculosis is susceptible to isoniazid and rifampin.
False. It is resistant to them
What bacteria is the most common cause of hospital-acquired infections?
Clostridium difficile
What are the symptoms of the Ebola virus?
Fever
Hemorrhaging
Blood clotting
What is the death rate of Ebola?
50-90%
How is Ebola transmitted?
Blood and bodily fluids
___ is currently the only FDA-approved vaccine to prevent Ebola Virus disease.
Ervebo
What virus has a similar clinical presentation to Ebola?
Marburg Virus
How is Marburg virus transmitted?
Bodily fluids
Handling ill or dead infected green monkeys and fruit bats
What are the symptoms of Zika virus disease?
Mild
However, in pregnant women, it is linked to miscarriage, stillbirth, and birth defects
How is the Zika virus spread?
Infected mosquitoes, specifically the Aedes species
What is MERS?
Middle East Respiratory Syndrome (Camel flu)
What virus is responsible for causing MERS?
MERS-coronavirus (MERS-CoV)