Microbiology (BIO 171) Final Exam (All answers correct)
3. True or False. Pathogenic strains of bacteria tend to grow slower than normal nonpathogenic bacterial strains.
False. Pathogenic strains of bacteria tend to grow faster than non-pathogenic strains at 37°C, which is why researchers may set incubators at 25°C to restrict its growth.
D A. Childhood skin disease near mouth/nose
E B. Infection of thin, transparent scleral tissue
A C. Infection occurs at time of birth
B D. Pus-filled lesions on skin or hair
5. Ophthalmia Neonatorum
C E. Ruptured pustules; treated with Penicillin
2. True or False. The causative agent of conjunctivitis can be either bacterial or viral.
True. There are bacterial (staph) and viral forms of conjunctivitis, both resulting in the inflammation of the conjunctiva and ‘pink eye.’
1. True or False. Although there is no cure for tetanus, it can be prevented through vaccination.
True. There is no cure for tetanus. However, tetanus is entirely preventable through vaccination.
2. Describe the symptoms and treatment regimen for someone infected with Clostridium perfringens.
Clostridium perfringens (also known as Gas gangrene) presents with muscle necrosis, swelling of infected areas, fever and intense gas production. Treatment entails removal of all infected tissue, often resulting in amputation of the affected areas, in conjunction with heavy antibiotic therapies.
3. Why does the alpha toxin (perfringolysin) produced during an infection of gas gangrene cause cell death?
The toxin perforates the membrane. It forms pores in the plasma membrane of host cells resulting in uncontrolled ion fluxes and eventually cell lysis and death.
1. The surrounds the capsid of some viruses.
2. True or False. You would expect to see a viral envelope on a virus infecting a plant cell.
False. The overwhelming majority of animal viruses are enveloped whereas the majority of plant or bacteria-infecting viruses are not.
3. Rank the following viruses based on their size from largest to smallest:
Variolavirus (~200nm) > Orthomyxovirus (100-150nm) > Poliovirus (~30nm)
1. While traveling abroad, should you be worried about coming into contact with either the Variola major or Variola minor viruses?
No. Both viruses are variants of smallpox and were eradicated in 1977. You would not need to worry about coming into contact with the virus.
What small (~30nm) single-stranded, non-enveloped RNA virus causes temporary or permanent paralysis by infiltrating (infecting) motor neurons within the spinal cord, brain stem or motor cortex?
Polio, also known as poliomyelitis.
3. Described the main underlining differences between the Salk and Sabin polio vaccine.
The Salk vaccine contained an inactivated form of the virus and was injected while the Sabin vaccine contained a live attenuated (weakened) form of the virus and was administered orally.
4. Which subtype of Influenza is the most virulent?