Micro Exam 3a

Question 1

portals of entry

Answer 1

• mucous membranes
• skin
• parenteral route

Question 2

adhesion

Answer 2

surface structure or macromolecule that binds a bacterium to specific surface

Question 3

lectin

Answer 3

any protein that binds to a carbohydrate

Question 4

ligand

Answer 4

surface molecule that exhibits specific binding to a receptor molecule on another surface

Question 5

fimbriae

Answer 5

filamentous proteins on surface of bacterial cells that may behave as adhesions for specific adherence

Question 6

glycocalyx

Answer 6

layer of fibers on the surface of bacterial cells which may be involved in adherence to surfaces

Question 7

capsule

Answer 7

detectable layer of polysaccharide on surface of bacterial cell which may mediate specific or nonspecific attachment

Question 8

lipopolysaccharide

Answer 8

distinct cell wall component of the outer membrane of gram-negative bacteria with potential structural diversity to mediate adherence

Question 9

nonspecific adherence

Answer 9

reversible attachment of bacterium to eukaryotic surface

• hydrophobic interactions
• electrostatic interactions
• brownian movement

Question 10

specific adherence

Answer 10

irreversible permanent attachment of microorganism to surface
- lock-and-key bonds

Question 11

ID50

Answer 11

infectious dose for 50% of the test population

• skin: 10-50 endospores
• inhalation: 10000-20000 endospores
• ingestion: 250000-1000000 endospores

Question 12

LD50

Answer 12

lethal dose of a toxin for 50% of test population

• botulinum: 0.03 ng/kg
• staphylococcal enterotoxin: 1350 ng/kg

Question 13

capsule

Answer 13

• prevents phagocytosis

- components: M protein, Opa protein and mycolic acid

Question 14

M protein

Answer 14

resists phagocytosis

Question 15

Opa protein

Answer 15

inhibits T helper cells

Question 16

mycolic acid

Answer 16

waxy lipid, resists digestion

Question 17

coagulase

Answer 17

coagulates fibrinogen in blood

Question 18

kinases

Answer 18

digest fibrin clots that are formed by body to isolate infection

Question 19

hyaluronidase

Answer 19

hydrolyzes hyaluronic acid, polysaccharide that holds certain cells together particularly connective tissue

Question 20

collagenase

Answer 20

hydrolyzes collagen, making up connective tissue

Question 21

IgA proteases

Answer 21

destroy IgA antibodies that are particularly important in first immune response

Question 22

antigenic variation

Answer 22

alteration of surface proteins in order to evade immune response

Question 23

what does disease occur?

Answer 23

• weakened host

- increased virulence

Question 24

how do bacteria penetrate host cell cytoskeleton?

Answer 24

• invasion, by altering structure of host cell

- using actin to move from one cell to the next

Question 25

effector molecules

Answer 25

secrete proteins into host cell in order to change things before the bacteria enters

Question 26

how does bacteria damage host cell? (4)

Answer 26

- uses hosts nutrients - causes direct damage in immediate vicinity of invasion - produces toxins, transported by blood and lymph, that damage sites far removed from original site of invasion - induce hypersensitivity reactions

Question 27

siderophores

Answer 27

mechanism used by bacteria to take in iron, host cell and pathogen compete for it. - can be salvaged by secreted siderophores - taken in as complex with the siderophore or released from siderophore prior to entry

Question 28

toxin

Answer 28

poisonous substance that contributes to pathogenicity

Question 29

toxigenicity

Answer 29

ability to produce a toxin

Question 30

toxemia

Answer 30

presence of toxin in host's blood

Question 31

toxoid

Answer 31

inactivated toxin used in a vaccine

Question 32

antitoxin

Answer 32

antibodies against specific toxin

Question 33

exotoxins

Answer 33

- come from gram (-) or gram(+) - genes carried on bacterial plasmid or phage - secreted into surrounding after metabolism

Question 34

endotoxin

Answer 34

- part of outer portion of cell wall of gram(-) - ex: lipid A - produce same symptoms from stimulating cytokine production - endotoxic shock

Question 35

types of exotoxins

Answer 35

- A-B toxins(Cholera) - membrane-disrupting toxins (pore-formers) - superantigens

Question 36

superantigens

Answer 36

- very intense T-cell immune response (cytokine) | - cause food poisoning or toxic shock syndrome

Question 37

process used by endotoxin

Answer 37

- macrophage ingests gram-negative bacterium - bacterium degraded in vacuole, releasing endotoxins that induce production of cytokines - cytokines released into the bloodstream by macrophages, through which they travel to hypothalamus - cytokines induce hypothalamus to produce prostaglandins which reset body's temp giving fever

Question 38

pathogenic properties of helminths

Answer 38

- use host tissue - presence of parasite interferes with host function - parasites metabolic waste can cause symptoms

Question 39

portals of exit

Answer 39

- respiratory tract, coughing and sneezing - gastrointestinal tract, feces and saliva - genitourinary tract, urine and vaginal secretions - skin - blood, biting arthropods and needles or syringes