Ch. 14 Mechanisms of Infectious Disease Flashcards
Define “mutualism”
Both host and microorganisms benefit
Define “parasitic”
Only the infecting organism benefits. Typically the host doesn’t die. “Infectious” means host sustains injury.
Define “virulence”
Disease producing potential
Define “pathogen”
Very virulent microorganisms
Define “saprophyte”
Environmental organisms that feed off dead/decaying organic material
- Usually fungi
Harmless to humans, but can be “opportunistic” organisms if host immune system is compromised
What are prions?
Abnormally shaped proteins that cause normal proteins to change their shape and thus become new prions
Propagation is unclear so difficult to treat
Cause neurodegenerative diseases of CNS
Eg. Creutzfeldt-jakob disease
Describe the structure of a virus
Protein coat surrounded by a nucleic acid core
Some have lipoprotein envelope
How does a virus replicate?
Incapable of replicating outside a living cell.
Inserts genome into host cell’s DNA, then uses cell energy.
How are viruses categorized?
Size, composition, how it replicates/transmits, resulting disease, etc.
What is a latent virus?
Enter cell insert genome, remain dormant until stimulated.
What is an oncogenic virus?
Can transform host cells to malignant cells during replication
What is an enterovirus?
Single stranded RNA virus.
What is a retrovirus group?
A virus with unique replication (eg HIV/AIDS)
What is a bacteria?
A small, simple structure that can live independently, but uses organisms’ nutrients.
Describe the structure of bacteria.
Cytoplasm covered by rigid cell wall that is susceptible to anti-bacterials.
Contains both DNA and RNA.
Have flagella (propel bacteria) and pilli (filaments that help adherance).
How do streptococci divide (what shape?)
Divide into chains
How do diplococci divide (What shape?)
Into pairs
How do staphylococci divide (what shape?)
Divide into clusters
Define “biofilm”
structured community of bacteria
Define “spores”
group waiting for stimulation to replicate
Define “aerobic”
requires oxygen
Define “anaerobic”
Hates too much oxygen
Define “facultatively anaerobic”
Can adapt to oxygen rich or poor environment
What are acid-fast bacilli?
They don’t stain (red or blue)
