Ch. 15

Question 1

What are the principal portals of entry and exit?

Answer 1

skin, mucous membranes, parenteral route

Question 2

ID50

Answer 2

infectious dose for 50% of the test population

Question 3

LD50

Answer 3

lethal dose of a toxin for 50% of the test population

Question 4

cell adherence virulence

Answer 4

adhesions/ligands bind to receptors on host cells, form biofilms

Question 5

capsule virulence

Answer 5

prevent phagocytosis

Question 6

List virulence factors

Answer 6

cell adherence, capsules, cell wall, enzymes, and toxins

Question 7

Damage caused by pathogens

Answer 7

disrupt host cell function, produce waste products, and toxins

Question 8

exotoxins

Answer 8

proteins produced inside the cell and then released, usually gram positive
protein
no fever
neutralized by antitoxin
small LD50

Question 9

endotoxins

Answer 9

part of the outer membrane of the cell wall of gram neg bacteria that are released when the cell dies and wall breaks apart
Lipid A
fever
not neutralized by antitoxin
large LD50

Question 10

mechanisms of action of A-B toxins

Answer 10

1. bacteria produce and release exotoxin
2. binds to cell wall
3. endocytosis
4. pinocytosis
5. A-part inhibits protein synthesis and B-part leaves the cell

Question 11

mechanisms of action of membrane-disrupting toxins

Answer 11

lyse host cells by making protein channels in the plasma membrane disrupting phospholipid bilayer

Question 12

mechanisms of action of superantigens

Answer 12

cause an intense immune response due to release of cytokines from host cells
symptoms- fever, nausea, vomiting, etc.

Question 13

cytopathic effect of viral infections

Answer 13

cause abnormal changes in the cell

Question 14

cause of symptoms- fungal

Answer 14

waste products

Question 15

cause of symptoms- protozoa

Answer 15

presence of protozoa, waste products

Question 16

cause of symptoms- helminths

Answer 16

presence of parasite interferes with host function, waste products

Question 17

algal disease

Answer 17

paralytic shellfish poisoning

Question 18

importance of antigenic variation

Answer 18

alter surface proteins

Question 19

siderophore

Answer 19

bacterial iron-binding proteins

Question 20

septic shock

Answer 20

a sudden drop in blood pressure induced by bacterial toxins

Question 21

toxemia

Answer 21

presence of toxin in the host’s blood

Question 22

antitoxins

Answer 22

antibodies against a specific toxin

Question 23

toxoids

Answer 23

inactivated toxin used in a vaccine