Test 2 - Practice Questions Flashcards
Describe PCR.
Used to make multiple copies of DNA. Each new DNA has one old strand and one new strand.
- Denaturation
- Annealing: Primers attached
- Extension/Elongation: taq polymerase synthesizes two new strands of DNA using the original strands as templates.
What is real-time PCR?
Also known as Quantative PCR.
Allows monitoring and quantification of increasing accumulation of PCR products/nucleic acid load as the reaction progreses.
Describe Metagenomics.
The study of the collective set of microbial populations in a sample by analyzing its entire nucleotide sequence content. Used for random detection of existing/new pathogens.
What is the importance of Genome sequencing?
- Pathogen detection
- Studies genetic variation
- ID of novel/undiscovered strains
- Development of diagnostics
- ID of genes associated with drug resistance
- Development of therapeutics
- Judging the efficacy of current vaccines and formulating new vaccine strategies.
Phylogenetic Analysis
The use of virus genome sequence data to study evolution of viruses and genetic relationships among viruses.
Microarray
The use of several thousands of known DNA probes to analyze target/sample DNA via hybridization on a glass/silicon chip. The sample DNA has a fluorescent signal that flouresces at intensities relative to the degree of hybridization.
It can be used to analyze hundreds of pathogens on a single chip.
Acyclovir is used to treat primarily what kind of viruses?
Herpes viruses
Herpesvirus in humans, Feline herpes virus 1 induced corneal ulcers and Equine Herpesvirus-1 enduced encephalomyelitis.
Describe the mechanism of action of Zidovudine or Axidothymidine (ZDV/AZT).
What kind of viruses is it used to treat?
It is a nucleoside analog of thymine. It uses reverse transcriptase to cleave it (after it has been phosphorylated by endogenous kinases) and is then inserted into the cDNA being synthesized. There is competitive inhibition for reverse transcriptase. It also has an azide group instead of a OH group on the pentose sugar, which blocks further nucleotide attachment.
It is a type of Anti-retroviral therapy. It is used to treat HIV and FIV. It slows the virus but does not eradicate it.
What is DIVA?
Differentiative Infected from Vaccinated Animals
Subunit markers are aded to the vaccine to be able to differentiate vaccinated animals from immunity developed through natural infection.
Describe the difference between isolation and quarantine.
Isolation applies to animals known to be ill with a contagious disease. It reduces contact with a susceptible host but relies on sensitivy of diagnostic tool.
Quarantine applies to those who have been exposed to a contagious disease and is enforced for the duration of the incubation period. It is not effective for chronically infected healthy shedders.
Which of the following is a sterilization method?
A. Disinfection
B. Moist Heat
C. Antisepsis
B. Moist Heat (e.g. Autoclave)
List the different sterilization methods.
- Moist heat (e.g. autoclave)
- Dry Heat (e.g. hot air oven)
- Chemical methods (e.g. ethylene oxide, ozone, hydrogen peroxide)
- Radiation (e.g. nonionizing UV and ionizing gamma/X-rays)
- Steril filtration (pore size <0.2 um)
TRUE/FALSE.
Antisepsis and disinfection are synonymous.
FALSE.
Disinfection refers to the elimination of many pathogenic organisms on inaminate objects. It is less effective than sterilization.
Antisepsis is the application of antimicrobial to skin or living tissue to inhibit/destroy microorganisms.
TRUE/FALSE.
All viruses of the poxvirus family are pleomorphic and brick-shaped.
FALSE.
Parapoxviruses are ovoid and covered with long thread-like surface tubules, which appear to be arranged in a criss-cross fashion.
What are the two types of infectious poxvirus particles?
Intracellular mature virus -IMV- (lysis; one membrane) & Extracellular enveloped virus-EMV- (budding, more virulent)
