Micro Bio chapter 11 pathogenesis
Endotoxins are released in large amounts only when cells lyse. True False
True
Which of the following is a major growth-limiting micronutrient that influences microbial growth? iron vitamin K sugar water
iron
Capsules are particularly important for? protecting bacteria from host defense mechanisms. making bacteria more vulnerable to host defense mechanisms. allowing bacteria to become more phagocytic. making bacteria less pathogenic.
protecting bacteria from host defense mechanisms.
Exotoxins are ________, but endotoxins are ________. carbohydrates / proteins proteins / lipopolysaccharide-lipoprotein complexes lipids / proteins lipopolysaccharide-lipoprotein complexes / proteins
proteins / lipopolysaccharide-lipoprotein complexes
________ are microbial infections acquired by hospital patients with noninfectious diseases because they are compromised hosts. Virulent infections Immunocompromised infections Healthcare-associated infections Pathogenic infections
Healthcare-associated infections
The best term to describe the general process by which microorganisms cause diseases is known as invasion. infection. pathogenesis. virulence.
pathogenesis.
________ are toxic proteins released from the pathogen during normal growth. Microtoxins Exotoxins Macrotoxins Endotoxins
Exotoxins
Gram-positive bacteria produce endotoxins. True False
False
Virulence genes may be located on mobile genetic elements. True False
True
What is the difference between adherence and colonization? Colonization occurs when a microbe begins to grow in host tissues whereas adherence occurs when the microbe initially attaches. Colonization occurs when transient microbes are on a tissue, whereas adherence is a more permanent attachment to cells. Colonization occurs when microbes begin to spread in host tissues, whereas adherence occurs when microbes first begin to reproduce in the host tissues. Colonization occurs when microbes begin to spread in host tissues, whereas adherence occurs when microbes initially attach.
Colonization occurs when a microbe begins to grow in host tissues whereas adherence occurs when the microbe initially attaches.
The toxic lipopolysaccharides produced by most gram-negative bacteria are called exotoxins. True False
False
Virulence refers to the overall ability of an organism to cause disease. True False
False
The dose of an antigen that kills 50% of animals in a test group and is used to estimate the virulence of a pathogen is known as Virulence-50. LD50 (lethal dose50) Death rate-50. Antigen dose50.
LD50 (lethal dose50)
Compared with an endotoxin, would a bacterial exotoxin generally be more likely to function after it had been significantly heated? Yes, because exotoxins are very heat stable compared to endotoxins. No, because exotoxins are carbohydrates and endotoxins are proteins. No, because exotoxins are heat-labile and less resistant to heating than endotoxins. Yes, because exotoxins are proteins and non-living but endotoxins are part of the bacterial cell wall.
No, because exotoxins are heat-labile and less resistant to heating than endotoxins.
Polio is transmitted by ingestion of water contaminated with feces containing polio virus. What portal of entry does polio virus use? Skin only Oral only Urogenital only Skin and oral Skin, oral, and urogenital
Oral only
An outer coat consisting of a dense, well-defined polymer layer surrounding a cell and used in attachment is called a lipopolysaccharide layer capsule pilus cytoplasmic membrane
capsule
Which of the following is NOT an example of an AB toxin? botulinum toxin shiga-like toxin tetanus toxin hemolysins
hemolysins
Which of the following is a way to prevent attenuation and maintain virulence in a bacterium? antibiotic therapy laboratory subculture polymerase chain reaction (PCR) inoculating an animal with the bacterium
inoculating an animal with the bacterium
The most frequently used portal of entry for pathogens is the mucous membranes of the gastrointestinal tract. parenteral route. All of these portals are used equally. mucous membranes of the respiratory tract. skin.
mucous membranes of the respiratory tract.
Tetanus toxin causes muscles to be unable to relax. muscles to be unable to contract. hemolytic uremic syndrome. severe diarrhea.
muscles to be unable to relax.
Pathogenicity is the ability of the host to inflict damage on the pathogen. of the host to resist damage by the pathogen. of the pathogen to inflict damage on the host. None of these are correct.
of the pathogen to inflict damage on the host.
Siderophores are inorganic molecules that help in active transport toxins that affect the gastrointestinal tract molecules that aid directly in attachment to host cells organic molecules that help pathogens take up iron
organic molecules that help pathogens take up iron
Which of the following is NOT important for the adherence of bacteria to host tissues? slime layer All of these answers could play a role in adherence capsule adhesins
slime layer
Staphylococcus aureus and Streptococcus pyogenes strains can produce ________ that cause the severe and sometimes life-threatening symptoms of toxic shock syndrome. superantigen toxins AB toxins endotoxin cytolytic
superantigen toxins
The collective term for the organisms living on or in the human body, as opposed to a general term for organisms in an environmental habitat, is the human microbiome. pathogens. transient microbial flora. the microbiota.
the human microbiome.
Put the following in order of what occurs first in an infection. Portal of Exit Damage to the Host Portal of Entry Adherence Evading Host Defenses
1. Portal of Entry 2. Adherence 3. Evading Host Defenses 4. Damage to the Host 5. Portal of Exit
________ is a damage or injury to a host organism that impairs its function. Infection Transmission Trauma Disease
Disease
Which of the following is a reason that specific pathogens tend to infect specific tissues? There are chemical and physical differences between tissues Tissues with neutral pH are colonized but those with acidic or alkaline pH are not Toxin specificy Microbes preferentially target external tissues, such as skin, as the environment is more favorable for their growth than inside the body
There are chemical and physical differences between tissues
Which of the following is TRUE about flagella? They are as important in adherence as pili and fimbriae. They may be involved in adherence to a lesser extent than pili and fimbriae. They are not involved in adherence and colonization at all. They are the most important structure in adherence.
They may be involved in adherence to a lesser extent than pili and fimbriae.
Because malnutrition can make the immune system weaker, the number of Vibrio cholera cells necessary to produce cholera in an exposed individual is drastically reduced in individuals with substantial malnutrition. True False
True
Invasion is the ability of a pathogen to enter into host cells or tissues, spread, and cause disease. True False
True
Pathogenicity islands are clusters of genes for virulence factors that are located together on the bacterial chromosome. True False
True
Cytolytic toxins are extracellular proteins are extracellular proteins that cause cell lysis and death by damaging the host cytoplasmic membrane damage host cytoplasmic membrane cause cell lysis and death
are extracellular proteins that cause cell lysis and death by damaging the host cytoplasmic membrane
The decrease or loss of virulence of a pathogen is referred to as attenuation disinfectivity aging lethal dose
attenuation