microbiology ch 15

Question 1

What is pathogenicity?

Answer 1

The ability to cause a disease

Question 2

What is virulence?

Answer 2

The degree of pathogenicity

Question 3

What are the three portals of microorganism entry into a host?

Answer 3

Mucous membranes, skin, and parenteral route

Question 4

What is the parenteral route of entry for microorganisms?

Answer 4

Entry through punctures, bites, infections; deposited directly into tissues when barriers are penetrated

Question 5

What is ID50?

Answer 5

The infectious dose of microbes for 50% of a sample population

Question 6

What is LD50?

Answer 6

Lethal dose of microbes for 50% of a sample population

Question 7

What does ID50 measure?

Answer 7

Virulence of a microbe

Question 8

What does LD50 measure?

Answer 8

Potency of a toxin

Question 9

What process do almost all pathogens use to attach to host tissues?

Answer 9

Adherence (adhesion)

Question 10

These on the pathogen bind to receptors on the host cells

Answer 10

Adhesins (ligands)

Question 11

Some bacteria have this around the cell wall that impairs phagocytosis

Answer 11

Glycocalyx capsule

Question 12

These cell wall components resist phagocytosis

Answer 12

M proteins

Question 13

These cell wall proteins allow attachment to host cells and fimbriae

Answer 13

Opa

Question 14

These cell wall components resist digestion

Answer 14

Wavy lipid (mycolic acid)

Question 15

These enzymes coagulate fibrinogen

Answer 15

Coagulases

Question 16

These enzymes digest fibrin clots

Answer 16

Kinases

Question 17

These enzymes digest the polysaccharides that hold cells together

Answer 17

Hyaluronidases

Question 18

These enzymes break down collagen

Answer 18

Collagenase

Question 19

These enzymes destroy IgA antibodies

Answer 19

IgA proteases

Question 20

What happens in antigenic variation?

Answer 20

Pathogens alter their surface antigens so antibodies are rendered ineffective

Question 21

These are surface proteins produced by bacteria that rearrange actin filaments of the cytoskeleton and cause membrane ruffling

Answer 21

Invasins

Question 22

What are two bacteria species that use actin to move from one cell to the next and through cells?

Answer 22

Shigella species and Listeria species

Question 23

What element is required for most pathogenic bacteria?

Answer 23

Iron

Question 24

These are proteins secreted by pathogens that bind iron more tightly than host cells

Answer 24

Siderophores

Question 25

These are poisonous substances produced by microorganisms

Answer 25

Toxins

Question 26

What are four health affects of toxins?

Answer 26

Fever, cardiovascular problems, diarrhea, and shock

Question 27

This is the ability of a microorganism to produce a toxin

Answer 27

Toxigenicity

Question 28

This is the presence of toxin in the host's blood

Answer 28

Toxemia

Question 29

This is the presence of toxin without microbial growth

Answer 29

Intoxication

Question 30

This type of toxin is produce inside and secreted by bacteria

Answer 30

Exotoxins

Question 31

These toxins are soluble in bodily fluids, destroy host cells and inhibit metabolic functions

Answer 31

Exotoxins

Question 32

During what phase are exotoxins secreted?

Answer 32

Log phase

Question 33

These are antibodies against specific exotoxins

Answer 33

Antitoxins

Question 34

These are inactivated exotoxins used in vaccines

Answer 34

Toxoids

Question 35

What are the two components of A-B toxins?

Answer 35

An enzyme (A) and a binding component (B)

Question 36

What do genotoxins do?

Answer 36

Damage DNA

Question 37

What do membrane-disrupting toxins do?

Answer 37

Lyse host cells by disrupting plasma membranes

Question 38

These membrane-disrupting toxins kill phagocytic leukocytes

Answer 38

Leukocidins

Question 39

These membrane-disrupting toxins kill erythrocytes by forming protein channels

Answer 39

Hemolysins

Question 40

These are hemolysins produced by streptococci

Answer 40

Streptolysins

Question 41

These cause an intense immune response due to release of cytokines from host cells (T cells)

Answer 41

Superantigens

Question 42

What symptoms do superantigens cause?

Answer 42

Fever, nausea, vomiting, diarrhea, shock, death

Question 43

These are part of bacterial cells, and not a metabolic product

Answer 43

Endotoxins

Question 44

What are two symptoms of endotoxins?

Answer 44

Fever and shock

Question 45

These may carry genes for toxins, productions of antibiotics, and enzymes

Answer 45

Plasmids

Question 46

This changes the characteristics of a microbe due to incorporation of a prophage

Answer 46

Lysogenic conversion

Question 47

These are visible effects of viral infection on a cell

Answer 47

Cytopathic effects

Question 48

These are granules or viral particle in the cytoplasm or nucleus of some infected cells

Answer 48

Inclusion bodies

Question 49

These are adjacent infected cells fused to form a very large multinucleate cell

Answer 49

Syncytium

Question 50

These are produced by virally-infected cells

Answer 50

Alpha and beta interferons

Question 51

These protect neighboring cells from viral infection

Answer 51

Alpha and beta interferons

Question 52

What are two ways alpha and beta interferons protect neighboring cells from viral infection?

Answer 52

Inhibit synthesis of viral proteins and host cell proteins; kill virus-infected host cells by apoptosis

Question 53

These produce toxic metabolic products that provoke an allergic response

Answer 53

Fungi

Question 54

Fungi produce these toxins that inhibit protein synthesis

Answer 54

Trichothecene toxins

Question 55

Fungi produce these that modify host cell membranes

Answer 55

Proteases

Question 56

Fungi have these that prevent phagocytosis

Answer 56

Capsules

Question 57

These are alkaloid fungi toxins that cause hallucinations

Answer 57

Ergot

Question 58

This is a carcinogenic toxin produced by Aspergillus

Answer 58

Aflatoxin

Question 59

These are produced by mushrooms and are neurotoxic; Phalloidin and amanitin are two examples

Answer 59

Mycotoxins

Question 60

The presence of these and their waste products causes symptoms

Answer 60

Protozoa

Question 61

What are three ways protozoa avoid host defenses?

Answer 61

Digesting cells/tissue fluids; growing in phagocytes; antigenic variation

Question 62

What is the neurotoxin produced by some algae?

Answer 62

Saxitoxin

Question 63

What does saxitoxin cause?

Answer 63

Paralytic shellfish poisoning

Question 64

These use host tissue for growth, produce large masses that cause cellular damage, and produce waste products that cause symptoms

Answer 64

Helminths

Question 65

What are the five portals of exit?

Answer 65

Respiratory tract; gastrointestinal tract; genitourinary tract; blood; skin