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Questions and Answers
What is the term meaning the ability to cause disease?
What is the term meaning the ability to cause disease?
What is the term for the measurement of pathogenicity?
What is the term for the measurement of pathogenicity?
What are the steps of microbial mechanisms?
What are the steps of microbial mechanisms?
Portal of entry, adherence, penetration into the host cell, evasion, damage to host tissue.
What are the three ways microbes get inside host?
What are the three ways microbes get inside host?
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What is the easiest and most often used mucous membrane for portal of entry?
What is the easiest and most often used mucous membrane for portal of entry?
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What is the mucous membrane portal of entry where most microbes are killed?
What is the mucous membrane portal of entry where most microbes are killed?
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What are some examples of the microbes that enter through the respiratory tract?
What are some examples of the microbes that enter through the respiratory tract?
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What are some examples of the microbes that enter through the GI?
What are some examples of the microbes that enter through the GI?
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What is the portal entry for STDs?
What is the portal entry for STDs?
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How do microbes enter through the GU?
How do microbes enter through the GU?
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What are some examples of the viruses that enter through the GU?
What are some examples of the viruses that enter through the GU?
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When microbes enter through hair follicles or sweat glands, what tissue are they using?
When microbes enter through hair follicles or sweat glands, what tissue are they using?
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What portal of entry is used when microbes enter through punctures, injections, or bites?
What portal of entry is used when microbes enter through punctures, injections, or bites?
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What are some examples of diseases that can cause infection using a specific mode of entry?
What are some examples of diseases that can cause infection using a specific mode of entry?
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If the infectious dose for a sample population is 50%, how would you express this measurement of virulence?
If the infectious dose for a sample population is 50%, how would you express this measurement of virulence?
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What does a low number in infectious dose or lethal dose measurements mean in regards to the virulence?
What does a low number in infectious dose or lethal dose measurements mean in regards to the virulence?
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If the lethal dose for a sample population is 50%, how would you express this measurement?
If the lethal dose for a sample population is 50%, how would you express this measurement?
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What is the difference between lethal dose measurements and infectious dose measurements?
What is the difference between lethal dose measurements and infectious dose measurements?
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In adherence, what helps the microbe adhere to the host?
In adherence, what helps the microbe adhere to the host?
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What is the term for communities of microbes and their products that attach to surfaces?
What is the term for communities of microbes and their products that attach to surfaces?
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Biofilm is what percentage of all bacterial infection?
Biofilm is what percentage of all bacterial infection?
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What must the microbe do to infect a host cell after it attaches to it?
What must the microbe do to infect a host cell after it attaches to it?
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When the microbe attaches to the host cell, what changes occur in the host cell?
When the microbe attaches to the host cell, what changes occur in the host cell?
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What are some of the ways that microbes employ evasion?
What are some of the ways that microbes employ evasion?
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What component of a cell wall does a microbe use in evasion?
What component of a cell wall does a microbe use in evasion?
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What enzyme clots fibrin?
What enzyme clots fibrin?
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How does the enzyme coagulase help the microbe in evasion?
How does the enzyme coagulase help the microbe in evasion?
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What enzyme breaks down fibrin?
What enzyme breaks down fibrin?
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How does the enzyme kinase help the microbe in evasion?
How does the enzyme kinase help the microbe in evasion?
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What enzyme breaks down hyaluronic acid?
What enzyme breaks down hyaluronic acid?
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How does the enzyme hyaluronidase help the microbe in evasion?
How does the enzyme hyaluronidase help the microbe in evasion?
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What enzyme breaks down collagen?
What enzyme breaks down collagen?
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What enzyme destroys IgA antibodies?
What enzyme destroys IgA antibodies?
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How does the microbe use antigenic variation?
How does the microbe use antigenic variation?
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How does the microbe damage the host tissues?
How does the microbe damage the host tissues?
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What are the steps that the siderophores go through to get the nutrients (iron) and bring it back to the bacterium?
What are the steps that the siderophores go through to get the nutrients (iron) and bring it back to the bacterium?
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What is the protein that binds iron stronger than hemoglobin?
What is the protein that binds iron stronger than hemoglobin?
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What is the direct damage to host tissues?
What is the direct damage to host tissues?
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What is the poisonous substance that is mostly protein enzymes?
What is the poisonous substance that is mostly protein enzymes?
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What is the measure of the virulence of the toxin?
What is the measure of the virulence of the toxin?
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What is the term that refers to a toxin in the blood?
What is the term that refers to a toxin in the blood?
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What are the two types of toxins?
What are the two types of toxins?
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What is the product that is produced by a bacterium, secreted by proteins, and is the most lethal substance known?
What is the product that is produced by a bacterium, secreted by proteins, and is the most lethal substance known?
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What are the antibodies produced by the body that can bind to the exotoxin?
What are the antibodies produced by the body that can bind to the exotoxin?
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What is the altered toxin used to stimulate the immune system?
What is the altered toxin used to stimulate the immune system?
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What are some examples of a toxoid?
What are some examples of a toxoid?
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What are some examples of diseases caused by bacterial exotoxins?
What are some examples of diseases caused by bacterial exotoxins?
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In A-B toxins, the A is what part of the exotoxin?
In A-B toxins, the A is what part of the exotoxin?
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In A-B toxins, the B is what part of the exotoxin?
In A-B toxins, the B is what part of the exotoxin?
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What kind of toxin inhibits protein synthesis and kills the cell?
What kind of toxin inhibits protein synthesis and kills the cell?
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What exotoxin causes lysis in the host cell plasma membrane?
What exotoxin causes lysis in the host cell plasma membrane?
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What exotoxin makes proteins in the plasma membrane and disrupts the phospholipid layer?
What exotoxin makes proteins in the plasma membrane and disrupts the phospholipid layer?
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What are some examples of membrane-disrupting toxins?
What are some examples of membrane-disrupting toxins?
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The membrane-disrupting toxin leukocidins is a toxin that kills what?
The membrane-disrupting toxin leukocidins is a toxin that kills what?
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The membrane-disrupting toxin hemolysins is a toxin that kills what?
The membrane-disrupting toxin hemolysins is a toxin that kills what?
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What is the term for an intense immune response or a super immune response?
What is the term for an intense immune response or a super immune response?
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What product produced by a bacterium is part of the cell wall and is only released when the cell wall is damaged?
What product produced by a bacterium is part of the cell wall and is only released when the cell wall is damaged?
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What response is present when a Gram-negative cell is ingested by a macrophage?
What response is present when a Gram-negative cell is ingested by a macrophage?
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What condition is due to a loss of blood pressure due to an endotoxin?
What condition is due to a loss of blood pressure due to an endotoxin?
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What condition results when tumor necrosis factor (TNF-a) makes capillaries permeable?
What condition results when tumor necrosis factor (TNF-a) makes capillaries permeable?
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Septic shock can cause large amounts of fluids to be lost and may even cause what?
Septic shock can cause large amounts of fluids to be lost and may even cause what?
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Which measure (LD or ID) is used to express virulence of pathogens or toxins?
Which measure (LD or ID) is used to express virulence of pathogens or toxins?
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In a biofilm, what is the first layer?
In a biofilm, what is the first layer?
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Dental plaque, algae on a pool, and soap scum are all examples of what?
Dental plaque, algae on a pool, and soap scum are all examples of what?
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How does the enzyme collagenase help with evasion?
How does the enzyme collagenase help with evasion?
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What exotoxins attack nerve cells?
What exotoxins attack nerve cells?
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What exotoxin attacks GI tract cells?
What exotoxin attacks GI tract cells?
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What exotoxin attacks heart cells?
What exotoxin attacks heart cells?
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Study Notes
Pathogenicity and Virulence
- Pathogenicity is the ability of an organism to cause disease.
- Virulence measures the degree or intensity of pathogenicity.
Microbial Mechanisms
- Infection begins with a portal of entry: mucous membranes, skin, and parenteral routes.
- Key steps for microbes: adherence to host, penetration into host cells, evasion of immune responses, and damage to host tissues.
Portals of Entry
- Respiratory tract is the most common mucous membrane portal for pathogens.
- Gastrointestinal tract serves as a portal where many microbes are killed by stomach acid and enzymes, but some can survive and disperse through feces.
- Genitourinary tract is a primary entry point for sexually transmitted diseases, with invaders entering via unbroken mucous membranes or through cuts.
Microbial Examples
- Common microbes entering via respiratory tract include pneumonia, tuberculosis, influenza, measles, and smallpox.
- Examples entering gastrointestinal tract include typhoid fever, poliomyelitis, and shigellosis.
- Notable examples of GU viruses are genital warts, herpes, and HIV.
Evasion Strategies
- Microbes employ various methods to evade host defenses including capsule use, cell wall components, and enzymatic action.
- Enzymes like coagulase help form fibrin clots, shielding microbes from white blood cells (WBC).
- Kinases break down fibrin, allowing microbes to escape immune isolation.
- Hyaluronidase facilitates movement through tissues by breaking down connective tissue.
Damage to Host Tissues
- Damage occurs through several mechanisms: cellular lysis, nutrient depletion, toxic waste accumulation, and toxin production.
- Siderophores are proteins that bind iron more tightly than hemoglobin, enabling bacteria to acquire essential nutrients.
Toxin Classification
- Toxins are poisonous substances, primarily protein enzymes, classified into exotoxins and endotoxins.
- Exotoxins are secreted proteins that can diffuse into the bloodstream and typically show high lethality.
- Antitoxins are antibodies formed by the body to neutralize exotoxins.
Special Types of Toxins
- A-B toxins inhibit protein synthesis; 'A' is the active component while 'B' binds to host cells.
- Membrane-disrupting toxins can lyse host cells, with leukocidins targeting WBCs and hemolysins affecting RBCs.
- Superantigens provoke intense immune responses.
Endotoxins
- Endotoxins are components of the Gram-negative bacterial cell wall, specifically lipopolysaccharides.
- They are released when bacterial cells die or when their wall is damaged, triggering inflammatory responses like fever and septic shock.
Septic Shock
- Occurs when endotoxins cause significant drops in blood pressure, potentially leading to death.
- TNF-a released by macrophages can increase capillary permeability, contributing to fluid loss and shock.
Biofilms
- Biofilms consist of communities of microbes that adhere to surfaces, significant in infections and resistance to treatment.
- The first layer in a biofilm is typically made up of bacteria, contributing to complex structures like dental plaque.
Additional Exotoxin Types
- Neurotoxins target nerve cells, while enterotoxins affect gastrointestinal cells, and cardiotoxins impact heart cells.
- Examples of diseases caused by exotoxins include botulism and staphylococcus food poisoning.
Studying That Suits You
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Description
Test your knowledge with these flashcards focusing on Chapter 15 of Microbiology. This chapter covers key terms related to pathogenicity, virulence, and microbial mechanisms. Perfect for students wanting to reinforce their understanding of how microbes cause disease.