Podcast
Questions and Answers
What does a website ending in .gov or .mil indicate?
What does a website ending in .gov or .mil indicate?
- The website is personal.
- The website is official and secure. (correct)
- The website is commercial.
- The website is a nonprofit organization.
What factor makes humans a desirable host for microorganisms?
What factor makes humans a desirable host for microorganisms?
- Humans are generally isolated from other organisms.
- The human body provides a nutrient-rich and warm environment. (correct)
- Humans have minimal interaction with microbes.
- Humans possess a unique immune system.
How does the normal flora typically behave in relation to pathogens?
How does the normal flora typically behave in relation to pathogens?
- Normal flora are identical to pathogens.
- Normal flora are always pathogenic.
- Normal flora only cause trouble when the immune system is compromised. (correct)
- Normal flora always causes disease.
What characteristic distinguishes dedicated pathogens from the normal flora?
What characteristic distinguishes dedicated pathogens from the normal flora?
What is an example of when normal flora can cause harm?
What is an example of when normal flora can cause harm?
How many bacterial, fungal, and protozoan cells are approximately present in the human body compared to human cells?
How many bacterial, fungal, and protozoan cells are approximately present in the human body compared to human cells?
What is the primary feature of microorganisms that can cause disease in humans?
What is the primary feature of microorganisms that can cause disease in humans?
Why do we typically view pathogens as hostile invaders?
Why do we typically view pathogens as hostile invaders?
What is required for the replication and expression of genetic information in DNA and RNA?
What is required for the replication and expression of genetic information in DNA and RNA?
What distinguishes prions from typical infectious agents?
What distinguishes prions from typical infectious agents?
Which of the following diseases is most well-known to be caused by prions?
Which of the following diseases is most well-known to be caused by prions?
What is the primary infectious property of prion proteins?
What is the primary infectious property of prion proteins?
Why are proteins usually able to find their correct folded conformation?
Why are proteins usually able to find their correct folded conformation?
What factor primarily determines whether a misfolded protein will behave like a prion?
What factor primarily determines whether a misfolded protein will behave like a prion?
Which of the following entities can cause infectious diseases?
Which of the following entities can cause infectious diseases?
How do most pathogenic bacteria promote their replication and spread in the host?
How do most pathogenic bacteria promote their replication and spread in the host?
What is a common characteristic of pathogens like protozoa and fungi during infection?
What is a common characteristic of pathogens like protozoa and fungi during infection?
What limitation do viruses face in replicating their proteins?
What limitation do viruses face in replicating their proteins?
What are virulence genes primarily responsible for in pathogenic bacteria?
What are virulence genes primarily responsible for in pathogenic bacteria?
What role do mobile bacteriophages play in pathogenicity?
What role do mobile bacteriophages play in pathogenicity?
Which component of cholera toxin is responsible for transferring the A subunit into host cells?
Which component of cholera toxin is responsible for transferring the A subunit into host cells?
What distinguishes Bacillus anthracis, the causative agent of anthrax, from other pathogens?
What distinguishes Bacillus anthracis, the causative agent of anthrax, from other pathogens?
What is the function of the A subunit of edema toxin in anthrax infections?
What is the function of the A subunit of edema toxin in anthrax infections?
What is the primary challenge in treating fungal and protozoan infections compared to bacterial infections?
What is the primary challenge in treating fungal and protozoan infections compared to bacterial infections?
Virulence factors are best described as what type of proteins?
Virulence factors are best described as what type of proteins?
What mechanism is commonly used by bacteria to inject toxic proteins into host cells?
What mechanism is commonly used by bacteria to inject toxic proteins into host cells?
How do most antibiotics preferentially treat bacterial infections?
How do most antibiotics preferentially treat bacterial infections?
What common feature do toxins produced by both cholera and anthrax share?
What common feature do toxins produced by both cholera and anthrax share?
Which of the following is a major difference between prokaryotic and eukaryotic cells relevant to antibiotic treatment?
Which of the following is a major difference between prokaryotic and eukaryotic cells relevant to antibiotic treatment?
Which toxin component of anthrax directly binds to host cell receptors to facilitate entry?
Which toxin component of anthrax directly binds to host cell receptors to facilitate entry?
What can trigger the transfer of virulence genes to an avirulent bacterium?
What can trigger the transfer of virulence genes to an avirulent bacterium?
Why are antifungal and antiparasitic drugs often more toxic than antibiotics?
Why are antifungal and antiparasitic drugs often more toxic than antibiotics?
Which of the following mechanisms is NOT necessary for a successful pathogen to survive and multiply in a host?
Which of the following mechanisms is NOT necessary for a successful pathogen to survive and multiply in a host?
What is one potential reason microorganisms evolve to cause disease?
What is one potential reason microorganisms evolve to cause disease?
Which of the following best describes obligate pathogens?
Which of the following best describes obligate pathogens?
What is a hallmark of bacterial infection as a result of the host's immune response?
What is a hallmark of bacterial infection as a result of the host's immune response?
Which of the following pathogens is considered an opportunistic pathogen?
Which of the following pathogens is considered an opportunistic pathogen?
What distinguishes facultative pathogens from obligate pathogens?
What distinguishes facultative pathogens from obligate pathogens?
Which infectious agent is characterized by being made only of protein and lacks a genome?
Which infectious agent is characterized by being made only of protein and lacks a genome?
How do fever and inflammation serve as defenses against infection?
How do fever and inflammation serve as defenses against infection?
Which of the following terms refers to bacteria that have the potential to cause disease only in specific circumstances?
Which of the following terms refers to bacteria that have the potential to cause disease only in specific circumstances?
What is characteristic of the pathogen Shigella flexneri?
What is characteristic of the pathogen Shigella flexneri?
Which aspect of pathogens contributes significantly to their ability to cause disease?
Which aspect of pathogens contributes significantly to their ability to cause disease?
What is the primary method by which viruses replicate within their host cells?
What is the primary method by which viruses replicate within their host cells?
Which of the following varieties of pathogens would most likely have variable mechanisms of causing disease?
Which of the following varieties of pathogens would most likely have variable mechanisms of causing disease?
What defines a fastidious pathogen?
What defines a fastidious pathogen?
Why is understanding both pathogen and host biology important in studying infectious diseases?
Why is understanding both pathogen and host biology important in studying infectious diseases?
What is dimorphism in pathogenic fungi?
What is dimorphism in pathogenic fungi?
Which organism is known for transitioning from a mold to a yeast form upon inhalation?
Which organism is known for transitioning from a mold to a yeast form upon inhalation?
What is the main way through which malaria parasites are transmitted to humans?
What is the main way through which malaria parasites are transmitted to humans?
How are gametes formed in Plasmodium falciparum infected individuals?
How are gametes formed in Plasmodium falciparum infected individuals?
What is a consequence of the sickle cell mutation in relation to malaria?
What is a consequence of the sickle cell mutation in relation to malaria?
What distinguishes viruses from bacteria and fungi?
What distinguishes viruses from bacteria and fungi?
What is the function of viral capsid proteins?
What is the function of viral capsid proteins?
What is the process by which enveloped viruses exit host cells?
What is the process by which enveloped viruses exit host cells?
What is a critical challenge in developing antiviral drugs?
What is a critical challenge in developing antiviral drugs?
Which of the following diseases has been effectively eradicated through vaccination?
Which of the following diseases has been effectively eradicated through vaccination?
How many distinct forms does Plasmodium falciparum have?
How many distinct forms does Plasmodium falciparum have?
Which of the following statements about viral genomes is true?
Which of the following statements about viral genomes is true?
What feature is common to both eukaryotic parasites and fungi?
What feature is common to both eukaryotic parasites and fungi?
What is the possible outcome of viruses causing chronic infections?
What is the possible outcome of viruses causing chronic infections?
Flashcards
How to identify an official government website
How to identify an official government website
Websites belonging to the US federal government often end with '.gov' or '.mil'.
What does 'https://' signify?
What does 'https://' signify?
The 'https://' prefix in a website address indicates a secure connection, ensuring the safety of your data while browsing.
Why do pathogens exist?
Why do pathogens exist?
A pathogen, like any other organism, strives to survive and reproduce. Their existence relies on exploiting a host organism for survival.
Why is a human body suitable for microorganisms?
Why is a human body suitable for microorganisms?
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What is normal flora?
What is normal flora?
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What is the relationship with viruses in the human body?
What is the relationship with viruses in the human body?
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How do pathogens differ from normal flora?
How do pathogens differ from normal flora?
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How can normal flora become pathogenic?
How can normal flora become pathogenic?
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Virulence Genes
Virulence Genes
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Virulence Factors
Virulence Factors
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Pathogenicity Islands
Pathogenicity Islands
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Virulence Plasmids
Virulence Plasmids
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Mobile Bacteriophages
Mobile Bacteriophages
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Pathogenicity
Pathogenicity
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Pathogen Evolution
Pathogen Evolution
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Cholera Toxin
Cholera Toxin
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B Subunit
B Subunit
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A Subunit
A Subunit
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Adenylyl Cyclase
Adenylyl Cyclase
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Anthrax Toxin
Anthrax Toxin
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Edema Toxin B Subunit
Edema Toxin B Subunit
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Edema Toxin A Subunit
Edema Toxin A Subunit
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Type III Secretion System
Type III Secretion System
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Pathogen adaptations
Pathogen adaptations
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Five steps of successful pathogen infection
Five steps of successful pathogen infection
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Pathogenesis
Pathogenesis
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Opportunistic pathogen
Opportunistic pathogen
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Obligate pathogen
Obligate pathogen
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Facultative pathogen
Facultative pathogen
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Fastidious pathogen
Fastidious pathogen
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Generalist pathogen
Generalist pathogen
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What are viruses?
What are viruses?
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What are bacteria?
What are bacteria?
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What are eucaryotic pathogens?
What are eucaryotic pathogens?
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What are prions?
What are prions?
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Host immune response and disease symptoms
Host immune response and disease symptoms
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Host-pathogen interactions
Host-pathogen interactions
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Exploiting host cell biology
Exploiting host cell biology
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Dimorphism
Dimorphism
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Histoplasmosis
Histoplasmosis
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Protozoan life cycle
Protozoan life cycle
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Malaria
Malaria
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Plasmodium falciparum
Plasmodium falciparum
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Sickle Cell Anemia
Sickle Cell Anemia
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Adaptation
Adaptation
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Bacteria, Fungi, and Eukaryotic parasites
Bacteria, Fungi, and Eukaryotic parasites
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Viruses
Viruses
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Viral Genome
Viral Genome
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Viral capsid
Viral capsid
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Viral replication
Viral replication
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Viral lysis
Viral lysis
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Viral budding
Viral budding
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Viral proteins
Viral proteins
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How do prion diseases occur?
How do prion diseases occur?
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What is Bovine Spongiform Encephalopathy (BSE)?
What is Bovine Spongiform Encephalopathy (BSE)?
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How do prions replicate?
How do prions replicate?
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What are pathogens?
What are pathogens?
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How do pathogenic bacteria differ from non-pathogenic bacteria?
How do pathogenic bacteria differ from non-pathogenic bacteria?
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Do all pathogens have the same life cycle?
Do all pathogens have the same life cycle?
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How do viruses replicate?
How do viruses replicate?
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What makes prions unique?
What makes prions unique?
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Study Notes
Pathogens and Infectious Diseases
- Pathogens, like parasites, are simply trying to survive and reproduce, often at the expense of a host organism.
- Humans are a desirable host environment due to warmth, moisture, and nutrient availability.
- Microorganisms have evolved to thrive within the human body.
Normal Flora vs. Pathogens
- The human body is a complex ecosystem with 1013 human cells and 1014 microbial cells (bacteria, fungi, protozoa).
- Normal flora are microbes typically residing in specific areas (skin, mouth, intestines, vagina). Majority are harmless.
- Pathogens differ; they can cause illness or death even in a healthy host. They possess adaptations for overcoming host defenses.
- Normal flora only cause trouble if the immune system is compromised or they enter sterile areas of the body.
Key Characteristics of Successful Pathogens
- Colonization: Establishing a foothold in the host.
- Finding a compatible niche for growth and nutrition.
- Evasion of the host's immune system (innate and adaptive).
- Replication utilizing host resources.
- Spread to a new host.
Pathogen Diversity and Disease
- Pathogens exhibit diversity in structure, size, and genetic content (DNA vs. RNA, enveloped vs. non-enveloped).
- Each pathogen causes disease through specific mechanisms.
- Pathogenic responses can sometimes enhance pathogen spread (e.g., herpes lesions aiding sexual transmission or diarrhea aiding caretaker infection.)
- Sometimes disease induction by a pathogen has no apparent advantage—symptoms are host immune system responses.
Major Types of Pathogens
- Viruses: Nucleic acid (DNA or RNA) wrapped in protein, utilizing host cells for replication. Range from common cold to severe illnesses like AIDS and smallpox.
- Bacteria: Larger, more complex, mostly free-living cells that rely on the host for nutrition, but can have specific adaptations to cause disease.
- Obligate pathogens: require host cells to replicate.
- Facultative pathogens: use external reservoirs like water or soil, only causing disease upon contact with a host.
- Opportunistic pathogens: normally harmless, but can become pathogenic in compromised hosts.
- Eukaryotic Parasites (Fungi, Protozoa, Worms):
- Fungal pathogens: can switch between yeast and mold forms during infection; example: Histoplasma capsulatum.
- Protozoan parasites: have complex life cycles, frequently requiring more than one host; example: Malaria (Plasmodium).
- Prions: Infectious proteins that cause neurodegenerative diseases like mad cow disease (BSE). They misfold normal proteins, initiating a chain reaction.
Virulence Genes and Factors
- Virulence genes, clustered in pathogenicity islands or plasmids, encode virulence factors (toxic proteins) that interact with host cells.
- Example: Cholera toxin from Vibrio cholerae: disrupts ion balance in gut cells causing diarrhea
- Example: Anthrax toxins from Bacillus anthracis: disrupt cellular signaling pathways.
Mechanisms of Pathogen Transmission
- Pathogens use diverse mechanisms for spreading—some pathogens spread from one infected host to another (direct or indirect); others rely on environmental reservoirs and host contact.
- Some pathogens are transmitted through vectors.
Preventing and Treating Infectious Diseases
- Antibiotics target bacterial macromolecular synthesis, avoiding damage to human cells.
- Antifungals and antiparasitics are often less effective and more toxic than antibiotics, due to similarities between pathogens and human cells.
- Vaccination is a highly effective prophylactic measure to prevent viral infections, as exemplified historically by smallpox eradication.
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