Micro Chapter 35 Flashcards
(42 cards)
1
Q
An organism that lives on or within another organism on which it is metabolically dependent is called a A) Host B) Parasite C) Pathogen D) Commensal
A
B
2
Q
When a parasite is growing and multiplying within or on a host, the host is said to have A) Pathogenicity B) A vector C) An infection D) A symptom
A
C
3
Q
Any organism or agent that produces a disease is known as a A) Pathogen B) Commensal C) Reservoir D) Vector
A
A
4
Q
The outcome of most host-parasite relationships depends on which of the following?
A) The number of microorganisms infecting the host
B) The virulence of the organism
C) The host’s defenses or degree of resistance
D) All of the above
A
D
5
Q
The degree or intensity of pathogenicity is known as A) Latency B) Infective capacity C) Virulence D) Infection
A
C
6
Q
Which of the following is an example of a sign of infection? A) Loss of appetite B) Malaise C) Pain D) Fever
A
D
7
Q
In the pattern of infection, a stage at which the disease is most severe and displays characteristic signs and symptoms is called the A) Incubation period B) Prodromal stage C) Illness period D) Convalescent period
A
C
8
Q
During which of the stages of infection is the host immune response typically triggered? A) Incubation period B) Prodromal stage C) Illness period D) Convalescent period
A
C
9
Q
The site or natural environmental location in which a pathogen normally resides is called a A) Source B) Reservoir C) Vector D) Hot zone
A
B
10
Q
Animate or inanimate first links in the infectious disease cycle are called A) Sources B) Reservoirs C) Vectors D) Pathogens
A
A
11
Q
An infected person who is a potential source of infection for others is called a A) Source B) Reservoir C) Carrier D) Resource
A
C
12
Q
An infectious disease that can be transmitted from animals to humans is called a(n) A) Opportunistic infection B) Zoonosis C) Contamination D) None of the above
A
B
13
Q
The physician that is credited for directly linking hand cleaning with decreasing rates of puerperal fever in newborns was A) Charles White B) Alexander Gordon C) Oliver Wendell Holmes D) Phillip Semmelweis
A
D
14
Q
Bacillus anthracis, the causative agent of anthrax, infects humans via
A) A bite from a mosquito
B) Inhalation, ingestion, or direct contact with spores
C) Food-borne transmission
D) Cat or dog scratch
A
B
15
Q
Borrelia burgdorferi, the causative agent of Lyme disease, infects humans via
A) A bite of an infected tick
B) Food-borne transmission
C) Direct contact with respiratory aerosols
D) Inhalation of contaminated soil and dust
A
A
16
Q
Which of the following diseases is spread via droplet nuclei? A) Tularemia B) Listeriosis C) Chicken pox D) All of the above
A
C
17
Q
Which of the following diseases is spread via sexual contact transmission? A) Common cold B) AIDS C) Encephalitis D) Measles
A
B
18
Q
Which of the following diseases is spread via vector-borne transmission? A) Lyme disease B) Encephalitis C) Plague D) All of the above
A
D
19
Q
Infectious dose 50 (ID50) is defined as
A) The number of microorganisms required to kill 50% of inoculated hosts
B) The number of microorganisms required to cause clinical disease in 50% of the inoculated hosts
C) The number of microorganisms required to infect 50% of the human population
D) The impact of infection with 50 microbial cells
A
B
20
Q
Organisms that can reside within the cells of the host or in the environment are known as A) Facultative extracellular pathogens B) Obligate extracellular pathogens C) Facultative intracellular pathogens D) Obligate intracellular pathogens
A
C
21
Q
Which of the following is an example of an obligate intracellular parasite of humans? A) Salmonella B) Influenza virus C) Chlamydia D) All of the above
A
C
22
Q
The susceptibility of a host to a pathogen depends on A) Pathogenicity of a microbe B) Non-specific host responses C) Specific host responses D) All of the above
A
D
23
Q
Various physical and chemical characteristics of a microbe that contribute to its pathogenicity are called A) Pathogenicity principles B) Virulence factors C) Fomites D) None of the above
A
B
24
Q
Genes on bacterial chromosomes and plasmids that code for virulence factors are called A) Fomites B) Jumping genes C) Infectivity genes D) Pathogenicity islands
A
D
25
Which of the following is true of pathogenicity island sequences?
A) The ends of the islands contain insertion-like elements
B) Variation of G+C sequences compared with the remainder of the genome
C) Exhibits open reading frames
D) All of the above
D
26
```
Which of the following adhesion mechanisms allow HIV to attach to human white blood cells?
A) Viral spikes
B) Glycocalyx anchors
C) Tapered hooks
D) Slime layer
```
A
27
```
Escherichia coli, the causative agent of diarrhea, attaches to host cells via
A) Slime layers
B) Viral spikes
C) Fimbrial adhesin
D) Suction discs
```
C
28
How do pathogens enter host tissues?
A) Production of lytic enzymes that damage host tissues
B) Tissue damage caused by other organisms
C) Disrupting the host cell surface
D) All of the above
D
29
```
The presence of viable bacteria in the bloodstream of the host is called
A) Septicemia
B) Bacteremia
C) Invasiveness
D) Contamination
```
B
30
Staphylococcus aureus invades host tissues by
A) Producing pyrogenic exotoxin B that degrades proteins
B) Producing leukocidins, pore-forming exotoxins that kill leukocytes
C) Producing coagulase, an enzyme that clots the fibrinogen in plasma and isolates the microbe
D) Producing hemolysins that lyse red blood cells and make iron available for microbial growth
C
31
```
Which virus evades the host immune response by fusing host cells allowing for movement to uninfected cells without exposure to antimicrobial fluids?
A) Smallpox virus
B) HIV
C) Hepatitis B virus
D) All of the above
```
B
32
Which of the following is a microbial mechanism for suppressing or evading the host's immune response?
A) Production of capsules that resemble host tissue components
B) Mutation and recombination of proteins on its surface
C) Down regulation of the level of expression of cell surface proteins
D) All of the above
D
33
A Pseudomonas aeruginosa biofilm evades the host immune response by
A) Lysing cells
B) Transferring microbes from one host cell to another
C) "Frustrating" phagocytosis
D) All of the above
C
34
Which of the following is true of bacterial biofilms?
A) Bacteria in biofilms are physiologically similar to planktonic forms
B) Bacteria coordinate gene expression to upregulate mechanisms that make the biofilm community less sensitive to antibiotics
C) Bacteria in biofilms rarely exchange plasmids
D) All of the above
B
35
```
Soluble, heat-labile proteins that are released into the surroundings as bacterial pathogens grow are called
A) Exotoxins
B) Endotoxins
C) Lipases
D) Domains
```
A
36
```
What type of exotoxin binds one portion to the host cell receptor while another portion enters the cell with enzyme activity that causes the toxicity?
A) AB toxin
B) Cytotoxin
C) Leukocidin
D) Superantigens
```
A
37
```
What types of exotoxin lyses host cells by disorganizing white blood cell membranes?
A) AB toxin
B) Cytotoxin
C) Leukocidin
D) Superantigens
```
C
38
```
Exotoxins that act by overstimulating T cells into releasing massive amounts of cytokines are called
A) AB toxin
B) Cytotoxin
C) Leukocidin
D) Superantigens
```
D
39
```
Lipopolysaccharide (LPS) in the outer membrane of Gram-negative bacterial cells is an example of
A) An endotoxin
B) An exotoxin
C) A cytokine
D) An endonuclease
```
A
40
```
Which type of bacterial molecules can indirectly induce a fever in the host by causing macrophages to release endogenous pyrogens that reset the hypothalamic thermostat?
A) Exotoxins
B) Endotoxins
C) Mycotoxins
D) All of the above
```
B
41
```
Toxins produced as secondary metabolites by fungi are called
A) Exotoxins
B) Endotoxins
C) Mycotoxins
D) Fungicides
```
C
42
Lethal dose 50 (ID50) is defined as
A) The number of microorganisms required to kill 50% of a group of hosts in a specified time
B) The number of microorganisms required to cause clinical disease in 50% of the inoculated hosts
C) The number of microorganisms required to infect 50% of the human population
D) The impact of infection with 50 microbial cells
A
