General 1

Question 1

Ribosomes of Bacteria vs fungi/parasites

Answer 1

B = 70s (30s+50s)

F and P = 80s (40s+60s)

Question 2

Differences in cellular membrane of Bacteria vs fungi vs parasites

Answer 2

B = no sterols except mycoplasmas which have cholesterol
F = ergosterol os major sterol
Parasites = sterols such as cholesterol

Question 3

Cell wall of Bacteria vs fungi vs parasites

Answer 3

B = (+) have very thick cell wall while (-) have very thin and they are made out of peptidoglycan
F = cell wall of complex carbohydrates like chitin
P = no cell wall

Question 4

Normal Flora of Blood

Answer 4

none

Question 5

Normal Flora of cutaneous surfaces

Answer 5

Staphylococcus epidermidis

can also find staph epidermidis and candidia

Question 6

Normal Flora of of nose

Answer 6

staphylococcus aureus

also some staph epidermidis

Question 7

Normal Flora of oropharynx

Answer 7

Streptococci viridans

Question 8

Normal Flora of ginigivial crevices

Answer 8

Anaerobes: bacteriodes, prevotella, fusobacterium streptococcus and actinomyces

Question 9

Normal Flora of stomach

Answer 9

none cus pH is too low

H pylori can colonize there but is not “normal”

Question 10

Normal Flora of colon

Answer 10

Breast fed babies have bifidobacterium

Adults have bacteriodes and prevotella

Question 11

Normal Flora of Vagina

Answer 11

Lactobacillus

Question 12

Mnemonic for Organisms with Capsules

Answer 12

Some Killers Have Pretty Nice Capsules
s = streptococcus pneumoniae
K = klebsiella pneumoniae
H = Haemophilus influenzae
P = pseudomonoas aeruginosa
N = neisseiria Meningitidis
C = cryptococcus neoformans= fungal

Question 13

Bacteria that display antigenic variation

Answer 13

N gonnorhea changes its pilli

trypanosoma brucei rhodesia/gambiense = sleeping sickness

Question 14

Bacteria with Type III secretion systems

Answer 14

E. coli
Salmonella
Yersinia
P. aerginosa
Chlamydia

Question 15

Hypersensitivity Reactions

Answer 15

I = Allergy = IgE mediated
II = Cytotoxic/Antibody mediated = IgM or IgG = rheumatic fever
III= Immune Complex = Post streptococcal acute glomerulonephritis
IV = Delayed type hypersensitivity = leprosy and chlamydia PID
V = Autoimmune disease

Question 16

Endotoxins

Answer 16

Lipopolysaccharide of Gram (-) = LPS
toxic portion is LIPID A
LPS is heat stable so cannot be converted to a toxoid to make a vaccine
LPS activates macrophages leading to release of TNFalpha, IL1 (fever) , and IL6. Bradykinin induced vasodilation leads to shock.
DIC due to activation of Hageman factor
Peptidoglycan and teichoic acids of gram (+) can also be endotoxins

Question 17

Exotoxins

Answer 17

Protein toxins that are secreted by bacteria
can be modified to a toxoid and made into a vaccine
A-B components where B binds to cell receptors and A is active/toxic component

Question 18

Cytolysins

Answer 18

Lyse cells from outside by damaging membranes

• C perfringens has alpha toxin that is a lecithinase that causes myonecrosis.
• staph aureus has alpha toxin that fomrs a pore in cell membrane

Question 19

Inhibitors of protein synthesis

Answer 19

Diptheria toxin and P. Aeruginosa’s exotoxin A affect ADP robosyl transferase and inactive eEF2 preventing elongation
Shigella’s shiga toxinand Enterohemmorhagic E coli’s verotoxin interferes with the 60s ribosomal subunit and

Question 20

Neurotoxins

Answer 20

C. tetani = clocks release of ihbitory transmitters glycine and GABA = spastic paralysis
C. botulinism = blocks release of excitatory acetylcholine = flaccid paralysis

Question 21

Super Antigens

Answer 21

STAPHYLOCOCCUS AUREUS = TSST-1

Streptococcus pyognes has exotoxin A that is simillar to TSST-1

Question 22

cAMP Producers

Answer 22

Enterotoxigenic E coli and Vibrio cholerae have a Heat Labile Toxin (LT) that stimulates adenyl cyclase open ion channels causing secretion of electrolytes and fluids
Bacillus Anthracis as EF = edema factor that causes edema and LEthal factor = LF = kills cells. 3 PROTEINS MAKE 2 toxins