Term
| What are the approximate sizes of viruses, bacteria, fungi, and parasites? |
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Definition
-Viruses 0.02-0.3μ
-Bacteria 0.3-2μ
-Fungi 3-10μ
-Parasites 15-25μ
In general it goes; 0.1, 1, & 10μ for viruses, bac, & euk |
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Term
| What are the membrane sterols for viruses, bacteria, fungi, and parasites? |
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Definition
-Viruses; none
-Bac; membrane, but no sterols
-Fungi; ergosterol is major sterol
-Parasites; cholesterol is major sterol |
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Term
| What makes up the cell wall in bacteria vs fungi? |
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Definition
-Bacteria have a simple wall made of peptidoglycan
-Fungi have a complex carb cell wall made of chitin, glucans, or mannans |
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Term
| What are the ribosomes for euk vs bac? |
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Definition
-Bac have a 70S made up of a 50S & 30S
-Euk have an 80S made up of 40S & 60S
-Notice you can't just add the subunits |
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Term
| What is polycistronic mRNA? |
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Definition
-Means mRNA that codes for multiple genes, such as in an operon (bacteria only)
-Some viruses also have polycistronic mRNA
-Eukaryotic mRNA is monocistronic |
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Term
| What is bacteremia vs. septicemia? |
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Definition
| -Both are bacteria in the bloodstream, but bacteremia is asymptomatic while septicemia is not |
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Term
| What are the normal flora of the bloodstream and stomach? |
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Definition
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Term
| Common and uncommon cutaneous flora (including urethra)? |
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Definition
-Staphylococcus epidermidis
-Staphylococcus aureus
-Various streptococci
-Yeast |
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Term
| Common and uncommon fora of the nose? |
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Definition
-Staph aureus
-S. epidermidis
-Diphtheroids
-Various streptococci |
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Term
| Common and uncommon flora of the oropharynx? |
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Definition
-**Viridans streptococci (including *strep. mutans)
-S. mutans secretes a biofilm that forms dental plaque
-Various streptococci
-Nonpathogenic Neisseria
-Nontypeable Haemophilus influenzae
-Candida albicans |
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Term
| Common bacteria of gingival crevices? |
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Definition
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Term
| Common fora of the colon (for babies and adults)? |
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Definition
In breast fed babies;
-*Bifidobacterium
In adults;
-*Bacteroides
-Escherichia
-Bifidobacterium |
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Term
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Definition
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Term
| What are the two major methods bacteria use to adhere for gram-positive and gram-negative? What about for bacteria in general? Example? |
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Definition
-Pili/fimbriae; for gram-
-Teichoic acids; for gram+
-Teichoic acids are structural polysaccharides that aid in attachment of bacteria
-Adhesins are a more general type of cell adhesion method (seen in pertussis toxin) |
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Term
| What do many bacteria possess to help them get into the mucosa? |
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Definition
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Term
| What are some of the bac that make biofilms? |
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Definition
-Streptococcus mutans (mouth)
-Staph. epidermidis (skin) |
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Term
| Give the common capsular microorganisms? What is the role of the capsule? |
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Definition
Mnemonic; Some Killers Have Pretty Nice Capsules
-Streptococcus pneumoniae
-Klebsiella pneumoniae
-Haemophilus influenzae
-Pseudomonas aeruginosa
-Neisseria meningitis
-Cryptococcus neoformans
-The capsule is outside of the cell wall and basically makes a viscid slimy layer that helps prevent phagocytosis |
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Term
| What are the other cell surface components that help inhibit phagocytosis and the bacteria producing them? |
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Definition
-Strep. pyogenes; M protein
-Neisseria gonrrhoeae; Pili
-Staph aureus; Protein A |
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Term
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Definition
| -Steal iron from host and import into bac. |
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Term
| Give two examples of antigenic variation as an evasive mechanism? |
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Definition
-N. gonorrhoeae have *pili that change proteins displayed (pili are commonly recognized by the immune system)
-Trypanosoma brucei rhodesiense and T.b. gambiense (east and west African sleeping sickness) use **phase variation where they alter surface antigens
-Salmonella commonly uses phase variation as well
-Much faster than change via mutation
-Changing constantly helps these microorganisms to become chronic infections as they continually evade detection (like in the case of gonorrhea) |
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Term
| What are two kinds of intracellular bac and how do they avoid killing? What do we often see associated with intracellular bacteria? |
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Definition
-M. tuberculosis; inhibits phagosome-lysosome fusion
-Listeria; escapes phagosome before fusion with lysosome
-Both avoid killing in macrophages in this manner, and macs respond with granuloma formation** typical of these types of infections |
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Term
| What are invasins? What uses them? |
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Definition
-Invasins are surface proteins that stimulate uptake by non-phagocytic cells
-Works well because regular cells won't have the intracellular killing machinery (safe haven for bad)
-Yersinia pseudotuberculosis uses this method and causes diarrhea |
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Term
| What is the type III secretion system? |
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Definition
-This is a tunnel from bacteria to host cell that delivers bacterial toxins directly to host cell
-Essentially an injection system of toxin delivery
-Many pathogens use it including E. coli, salmonella, and others |
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Term
| Much of the damage to tissue is caused by our own bodies reaction (hypersensitivity). Give four methods this works in bacterial infections and examples of each? |
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Definition
-Cross-reaction of antibodies with self antigens; such as in rheumatic fever (type II HS)
-Delayed hypersensitivity and granulomatous response; from intracellular pathogens - neurological damage in leprosy, cavitation in TB, fallopian tube blockage in PID
-Immune complex formation; seen in post-streptococcal acute glomerulonephritis (type III HS)
-Peptidoglycan-teichoic acid; released from gram+ bac after death and acts as structural toxin and chemotaxin for neutrophils (inflammation) |
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Term
| Give an example of when the large size of an organism can lead to damage? |
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Definition
| -Ascaris lumbricoides is the largest round worm infecting humans (can grow to 35cm) and can block off the bile duct |
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Term
| Another way we can get physical damage is from aggressive tissue invasion. What is the parasitic protozoan that can cause intestinal ulceration from it's aggressive invasion? |
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Definition
-Entamoeba histolytica (very common worldwide)
-Causes ulceration and possible release of intestinal flora, compounding the problem |
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