Micro Lecture 3

Question 1

Commensalism

Answer 1

One org. benefits, other is unaffected + / 0

Question 2

Mutualism

Answer 2

Both orgs. benefit + / +

Question 3

Parasitism

Answer 3

One org. benefits at expense of another + / -

Question 4

Microbial antagonism

Answer 4

Competition between microbes

Question 5

Bacteriocins

Answer 5

Proteins that inhibit growth of other bacteria

Question 6

Opportunistic pathogens

Answer 6

Cause disease in compromised host

Question 7

Koch’s postulates

Answer 7

Prove the cause of infectious disease (same pathogen, isolated, cause disease in healthy animal, isolated from inoculated animal)

Question 8

Name two microbes that have never been cultured.

Answer 8

Syphilis, leprosy

Question 9

Signs

Answer 9

Changes (symptoms) that can be measured/observed

Question 10

Incidence

Answer 10

Number of people who develop disease during particular time period

Question 11

Prevalence

Answer 11

Number of people who have disease at a specified time

Question 12

Focal infection

Answer 12

Systemic infection that began as local infection

Question 13

Reservoirs of infection

Answer 13

Human, animal, nonliving (water, soil)

Question 14

Secondary infection

Answer 14

Opportunistic infection after primary infection

Question 15

Subclinical disease

Answer 15

No noticeable signs or symptoms

Question 16

Indirect contact transmission

Answer 16

Spreads to host by nonliving object (fomite), ex. syringes

Question 17

Droplet transmission

Answer 17

Airborne droplets less than 1 meter

Question 18

Vectors

Answer 18

Arthropods, via mechanical (carries on feet) or biological (bites, feces)

Question 19

Vehicle transmission

Answer 19

Waterborne, foodborne, airborne

Question 20

Nosocomial infections

Answer 20

Hospital associated infections, microorganisms, weakened status of host, chain of transmission

Question 21

Control measures to reduce pathogens

Answer 21

Handwashing, disinfection, cleaning instruments, disposable bandages

Question 22

Infectious dose for 50% of sample pop.

Answer 22

ID 50

Question 23

Lethal dose for 50% of sample pop.

Answer 23

LD 50 (potency of toxin)

Question 24

How do pathogens attach to host tissues?

Answer 24

Adherence via adhesins (ligands bind to receptors on host)

*Microbes form biofilms

Question 25

List cell wall components

Answer 25

M protein: resists phagocytosis Opa protein: allows attachment to host Waxy lipid: resists digestion

Question 26

Coagulase

Answer 26

Coagulates fibrinogen

Question 27

Kinase

Answer 27

Digests fibrin clots

Question 28

Hyaluronidase

Answer 28

Digests polysaccharides that hold cells together

Question 29

Collagenase

Answer 29

Breaks down collagen

Question 30

IgA proteases

Answer 30

Destroys IgA antibodies

Question 31

Antigenic variation

Answer 31

Pathogens alter surface antigens (antibodies rendered ineffective)

Question 32

Invasins

Answer 32

Surface proteins produced by bact. that rearrange actine filaments (membrane ruffling)

Question 33

Siderophores

Answer 33

Proteins secreted by pathogens, bind iron (Fe) more tightly than host cells, ex. enterobactin

Question 34

Exotoxins

Answer 34

gram +, A-B toxins, membrane disrupting, genotoxins

Question 35

Antitoxins

Answer 35

Antibodies against specific exotoxins

Question 36

Toxoids

Answer 36

Inactivated exotoxins used in vaccines

Question 37

A-B toxins

Answer 37

Contain enzyme and binding components, ex. diptheria toxin

Question 38

Leukocidins

Answer 38

Kill phagocytic leukocytes

Question 39

Hemolysins

Answer 39

Kill erythrocytes via protein channels

Question 40

Streptolysins

Answer 40

Hemolysins produced by streptococci

Question 41

Superantigens

Answer 41

Intense immune response due to release of cytokines from host cell

Question 42

Genotoxins

Answer 42

Damage DNA

Question 43

Lipid A

Answer 43

Endotoxin, part of LPS of gram neg. bact., released during bact. multiplication/when gram neg. bact. die

Question 44

Lysogenic conversion

Answer 44

Changes characteristics of microbe due to incorporation of bacteriophage

Question 45

Infective agent of Chlamydiae

Answer 45

Elementary body

Question 46

How is Rickettsia transmitted?

Answer 46

Insect/tick bites