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Microbial Growth: Environment. Microbial Growth: Body. Infections, Infectious Diseases Epidemiology. Viruses, Viroids, Prions. Potpourri. 100. 100 . 100. 100. 100. 200. 200. 200. 200. 200. 300. 300 . 300. 300. 300. 400. 400. 400. 400. 400. 500. 500. 500. 500. 500.
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Microbial Growth: Environment Microbial Growth: Body Infections, Infectious Diseases Epidemiology Viruses, Viroids, Prions Potpourri 100 100 100 100 100 200 200 200 200 200 300 300 300 300 300 400 400 400 400 400 500 500 500 500 500
A cleaning that kills All microbes.
What type of microbe is the most resistant to disinfectants? Least resistant?
Endospores Enveloped Viruses
Which disinfectant would be more efficient: Phenol Coefficient of 154 against S. aureus or Phenol Coefficient of 137 against S. typhi
Cannot tell when used against two different organisms
Which organisms are used for the Use-Dilution Test?
Pseudomonas aeruginosa Salmonella cholerasuis Staphylococcus aureus
Which of the following chemicals does not fit with the others? Phenol Surfactants Oxidizing agents Heavy metals
Oxidizing agents, it has a high level of activity, the others are low or intermediate
Who coined the term antibiotics?
Which two bacterial genera produce the most antibiotics?
List the 6 modes of action of antibacterial drugs
Inhibition of cell wall synthesis • Inhibition of protein synthesis • Disruption of cytoplasmic membrane • Inhibition of general metabolic pathway • Inhibition of DNA or RNA synthesis • Inhibition of attachment or recognition
Describe the benefits and drawbacks of using a broad-spectrum antibiotic.
Benefit is that the pathogen will most likely be targeted by the drug Drawback is that continual use of the drug can lead to super infections from normal microbiota.
Here are the results of a MIC and MBC test: 0.0 0.02 0.04 0.08 0.16 0.36 What is the minimum inhibitory concentration? What is the minimum bactericidal concentration?
MIC = 0.08 MBC = 0.16
What are the three basic shapes of viruses? *Bonus* give an example of a virus for each shape
Helical- tobacco mosaic Polyhedral- rhinovirus (common cold) Complex- small pox
List 4 characteristics that all viruses share.
Acellular • Infectious • Contain nucleic acid • Not capable of metabolic activity on • their own • Capsid
List in order the steps of viral replication in a general lytic replication cycle.
attachment • entry • synthesis • assembly • release
Say an enveloped animal virus entered a host cell by membrane fusion. What must happen before the virus can begin synthesis?
Give one similarity and two differences between lysogeny and latency.
Similar in that they both can remain dormant and have no • viral activity. • Differences in that some latent viruses may not • incorporate into host chromosome where lysogenic phages • always do. • Also when latent viruses become incorporated into a • chromosome, it will remain forever, no induction occurs.
Name the three types of symbiosis and give an example of each. (example need not be related to Microbiology)
Mutualism Commensalism Parasitism
Define normal microbiota, and explain the difference between resident and transient microbiota.
Normal microbiota are organisms that • colonize the surface of the body without • normally causing disease. • Resident microbiota are part of the host • for the life of the host. • Transient microbiota remain part of the host • for brief periods of time.
Describe three conditions that might allow normal microbiota to become an opportunistic pathogen.
Immune suppression • Changes in normal microbiota • Introduction of a member of the • normal microbiota into an • unusual site in the body.
Describe the three types of virulence factors that contribute to pathogenicity.
Extracellular enzymes- includes Hyaluronidase, collagenase, coagulase, and kinases. Allows for pathogen to maintain an infection, invade further, and avoid body defenses. Toxins- consist of exotoxins and endotoxins. Exotoxins consist of cytotoxins, neurotoxins, and enterotoxins. Endotoxins are part of Gram (-) cell wall structure. Antiphagocytic Factors- include capsules and antiphagocytic chemicals.
Name 4 portals of entry, and give a specific example for each.
Skin- hair follicles, sweat glands, abrasions, cuts ,scrapes. Mucous Membranes- mouth, nose, lungs, esophagus, urinary lining, reproductive lining, gastrointestinal lining. Placenta- placenta Parenteral Route- punctures, cuts, bites, stab wounds, surgery.
Which types of viruses carry their own polymerase enzymes?
ssRNA – carry RNA-dependent RNA polymerase Retroviruses carry RNA-dependent DNA polymerase
Which of the following does not match the others? Why? Pain Nausea Anemia Malaise Itching Fatigue Sore throat
Anemia, it is a sign all the others were symptoms
What is more effective in stopping microbial growth: Freezing slow or freezing fast. Why?
Freezing slow: it allows ice crystals to form and puncture cell membranes.
Name four mechanisms of action certain antibiotics have been found to block protein synthesis.
Bind to 30S subunit, changing shape • Bind to tRNA docking site, blocking tRNA’s • Bind to 50S subunit, blocking growing a.a. chain • Bind to 50S subunit, blocking mRNA movement
Name four diseases caused by prions.