Microbiology Final Review

Miscellaneous

100

What is a toxic dose and therapeutic dose?

Toxic dose- the maximum limit of the chemotherapeutic that can be tolerated by a human Therapeutic does-the minimum amount of chemotherapeutic needed to eliminate the pathogen from the host

200

Why are sulfonamides used as a chemotherapeutic?

Interferes with folic acid synthesis which is necessary for nucleic acid synthesis Competitive inhibition - competes for enzyme active site

300

If i wanted to prevent tRNA attachment to the small subunit of bacteria, what chemotherapeutic would I used?

Tetracylines

400

Explain and describe the mechanisms of antibiotic resistance 

Altered metabolic pathway Bacterial enzymes mutate to be unaffected by antibiotic or use an alternate metabolic pathway 2. Antibiotic inactivation Penicillinase cleaves Beta-lactam groups 3. Reduced permeability or active export Proteins can be used to pump antibiotic out of cell 4. Target modification Bacterial targets mutate so antibiotic no longer binds to its target

500

If I wanted to identify that a certain bacteria caused a disease how would I go about doing this?

answers might very but should include components of Koch's postulates 

Bacterial Genetics

100

How are prokaryotic and eukaryotic mRNAs processed differently?

prokaryotic-RNA transcribed and translated in cytoplasm Some mRNAs can hold information for more than one protein Polycistronic mRNA eukaryotic-Most eukaryotic genes do not have continuous protein-coding regions Exons and Introns

200

In the presence of lactose or allolactose , does RNA polymerase bind to the the lac operon? why or why not?

Yes, because the inducer binds to the repressor so the repressor is not longer bound to the operon. Therefore, RNA polymerase can transcibe the genes for lactose breakdown

300

If there is continuous synthesis of he mRNA strand by RNA polymerase, what could there be a mutation in?

mutation in the termination factors, so there could be a mutation in Rho protein or no longer form hairpin loop

400

What is the role of primase?

it provides a 3'OH for DNA polymerase to add the next nucleotide to

500

Describe how a bacteria would obtain a virulence factor and what type of virulence factor could this be?

answers may vary but should contain conjugation, (horizontal gene transfer). An example or virulence factor could be a toxin.

Immune System

100

When someone is first infected with a disease, what anitbody is produced first?

IgM

200

What type of toll-like receptor senses RNA viruses?

TRL-3

300

Explain how Natural Killer Cells induce cell death .

uses peforin to deliver granzyme which activates apoptosis

400

What do TH2 helper cells recognize and how do they give "help" to Cytokine B?

recognize MHC class II + antigen and IL-2 helps B cell divide (clonal expansion) IL-4/5 help B cell become plasma cell and produce antibodies 

500

List and describe the different stages of Phagocytosis

Chemotaxis : Cytokine, chemokines, complement fragments 

Adhesion :Microbes coated w/ opsonins 

Ingestion : Via pseudopods 

Digestion : Phagolysozome—hydrolytic enzymes Formation of reactive nitrogen and oxygen species to kill. Superoxide, hypochlorite, nitric oxide, H2O2 

Diseases 1

100

What are the virulence factors for listeria monocytogenes? 

Ahesins, Invasins, Listerolysin

200

This gram positive, non-motile bacillus is transmitted by respiratory droplets and causes diphtheria . Name this bacterium and its virulence factor(s)?

Corynebacterium diphtheriae, AB toxin: Inhibits epithelial cell protein synthesis, leads to cell death

300

A patient comes into the ER with cramping, nausea, flatulence, foul-smelling watery diarrhea. What is causing these symptoms? (ie name the bacteria ,virus,fungus or parasite) and what treatment would you give this patient

Giardia intestinalis (lamblia), Nitroimidazole( impairs DNA in anaerobic environments

400

A 5 year child comes into the emergency room with a fever and vesicular lesions all over his body. What type of virus is this child infected with? How would you treat this virus and what do you want to avoid giving the child? Why?

Varcella voster virus, NO aspirin for varicella in children (Reye’s syndrome); acyclovir or valacyclovir for zoster

500

This virus is a single stranded RNA (+), enveloped that infects respiratory epithelium. Name this virus and explain the concern if pregnant women is infected with this virus. What should you avoid giving a pregnant patient infected with this virus?

Hep C and the vaccine MMR(V); live, attenuated.  

Diseases 2

100

What phylum has a percentage of G-C below 50% and which has a percentage above 50%?

Below- firmicutes 

Above- Actinobacteria 

200

A person comes into the ER fever, inflammation of small blood vessels joint pain. What is the casual organisms and name the disease?

Step, pyogenes and rheumatic fever

300

How would you treat someone infected with Cryptococcus neoformans? What is the mode of action of this treatment?

Amphotericin B : Targets cell membranes of fungi  Binds to sterols in membrane, causing leaking of cations 

400

A patient comes into the ER with fever, abdominal pains, and clay-colored stools. Further assessment of the patient, reveals that the patient’s liver has cirrhosis. You identify this virus to have a double stranded circular DNA, qhat type of virus is this patient infected with? What’s your diagnosis? What treatment would you prescribe and why?

Hep B, Viral antigen detection from bodily fluids (using antibodies) , interferon; lamivudine (3TC) or entecavir ( Reverse transcriptase inhibitor)

500

A woman comes in with itching, pain with urination, and a yellow green discharge. A yeast infection is ruled out. What possible disease could this be and what is the causal organism? What is significant about this disease? 

Trichonomasis, Trichomonas vaginalis Sexually transmitted protozoal disease .Humans only reservoir, No cyst stage