Session 1 Flashcards
(35 cards)
What are prions?
Misfolded self-replicating proteins that do not have nucleic acids.
- Often transmitted in neurosurgery.
What are the sizes of microorganisms?*
Prions -> Viruses -> Mycoplasma -> Mitochondria -> Bacteria -> Eukaryotic -> Worms
Why are mitochondria and bacteria similar size?
Endosymbiotic theory - mitochondria evolved from bacteria.
What are obligate intracellular organisms?
Organisms that are deficient in some genetic material and therefore need host DNA to make up for it.
What is the structure of a typical virus?*
- Lipid envelope
- Protein coat that surrounds nucleic acids
- Nucleic acid (DNA/RNA) in middle
- Spikes for attaching to specific cell surfaces - initiate virus replication
Why are some people immune to HIV?
Their lymphocytes do not have the specific surface protein, so the virus can’t bind.
What is an example of a single stranded, non enveloped DNA virus?
Parvovirus 19
- Red cheeks in children
- Spontaneous bleeding in adults
What are double stranded, non enveloped DNA viruses?
- Adenovirus
- HPV (causes laryngeal/cervical cancer)
What are double stranded, enveloped DNA viruses?
- Herpes (genital, cold sore)
- Hep B (chronic liver infection)
- Molluscum contagiosum (wart-like skin that can get infected)
What are single stranded, positive strand, icosahedral (‘20 faces’) non-enveloped RNA viruses?
- Enterovirus (polio)
- Norovirus
- Hepatitis A + E
What are single stranded, positive strand icosahedral/helical enveloped RNA viruses?
- HIV
- Hep C
- Rubella
- Encephalitis
What are single stranded, negative strand helical enveloped RNA viruses?
- Ebola
- Measles
- Influenza
What is a double-stranded, icosahedral non enveloped RNA virus?
Rotavirus (gastroenteritis)
What is the overview of viral infections?*
SLIDE 9!
What are bacteriophages?*
- Viruses that can infect bacteria
- Multiply in bacteria and then break bacterial cell wall to release the virus copies
What is the structure of a typical bacterium?*
- Flagellum
- Capsule
- Cell wall (peptidoglycan)
- Plasmid (contains genes for virulence factors and antibiotic resistance, can be transmitted between species of bacteria)
What are different bacterial shapes?
- Coccus (circle)
- Spirillus (spiral, v. rare)
- Bacillus (rod)
How are cocci arranged?
- Clusters (staphylococci)
- Chains (streptococci)
What is the difference between gram negative and gram negative bacteria?
Gram negative bacteria have an outer membrane made of lipopolysaccharide and protein which gram positive bacteria do not have.
What are anaerobes?
Bacteria that can survive in the absence of oxygen.
What are aerobes?
Microorganisms that can survive in the presence of oxygen (many can also survive anaerobically)
What are obligate aerobes?
Organisms that require oxygen for survival
What are obligate anaerobes?
Organisms that require an oxygen-free environment for survival, unless they’re able to form spores.
What are medically important gram positive cocci?
- Staph aureus
- Coagulase negative staph
- Alpha haemolytic streptococci
- Beta haemolytic streptococci
- Strep pyrogenes
- Streptococcus pneumoniae
- Enterococcus faecalis
