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Questions and Answers
What feature distinguishes fungi from plants?
What feature distinguishes fungi from plants?
Which statement accurately describes the cell structure of fungi compared to bacteria?
Which statement accurately describes the cell structure of fungi compared to bacteria?
Which type of fungi is characterized as multicellular and reproduces by forming airborne spores?
Which type of fungi is characterized as multicellular and reproduces by forming airborne spores?
What is a significant difference between septate and non-septate hyphae?
What is a significant difference between septate and non-septate hyphae?
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Which of the following defines saprotrophic fungi?
Which of the following defines saprotrophic fungi?
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In what form can fungi exist when located within animal tissue?
In what form can fungi exist when located within animal tissue?
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What distinguishes mycorrhizae from lichens?
What distinguishes mycorrhizae from lichens?
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How do fungi primarily reproduce asexually?
How do fungi primarily reproduce asexually?
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Which of the following conditions does not influence the classification of fungi?
Which of the following conditions does not influence the classification of fungi?
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What makes fungi facultative anaerobes distinct from obligate anaerobes?
What makes fungi facultative anaerobes distinct from obligate anaerobes?
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What differentiates a secondary cell culture from a primary cell culture?
What differentiates a secondary cell culture from a primary cell culture?
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Which prion protein is known to be abnormal and associated with disease?
Which prion protein is known to be abnormal and associated with disease?
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What is the primary characteristic of a communicable disease?
What is the primary characteristic of a communicable disease?
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What type of cell culture is characterized by being not affected by contact inhibition?
What type of cell culture is characterized by being not affected by contact inhibition?
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Which antiviral drug works specifically by inhibiting genome replication?
Which antiviral drug works specifically by inhibiting genome replication?
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Which of the following best defines the term 'syndrome'?
Which of the following best defines the term 'syndrome'?
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What role do host cells play in the cultivation of animal viruses?
What role do host cells play in the cultivation of animal viruses?
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What is the significance of plaques in the study of bacteriophages?
What is the significance of plaques in the study of bacteriophages?
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What is a primary characteristic of iatrogenic diseases?
What is a primary characteristic of iatrogenic diseases?
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What defines the prodromal phase of a disease?
What defines the prodromal phase of a disease?
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What is a defining characteristic of Basidiomycota among fungal phyla?
What is a defining characteristic of Basidiomycota among fungal phyla?
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Which of the following fungal species is associated with Candidiasis?
Which of the following fungal species is associated with Candidiasis?
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What type of reproduction do Zygomycota utilize for producing diploid zygotes?
What type of reproduction do Zygomycota utilize for producing diploid zygotes?
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Which phylum does not possess septa in its hyphae?
Which phylum does not possess septa in its hyphae?
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What is the primary cause of Histoplasmosis?
What is the primary cause of Histoplasmosis?
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What is the primary function of the polar tubule found in Microsporidia?
What is the primary function of the polar tubule found in Microsporidia?
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What type of RNA serves as a template for synthesizing +ssRNA in viral replication?
What type of RNA serves as a template for synthesizing +ssRNA in viral replication?
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What common condition is caused by the fungus Trichophyton?
What common condition is caused by the fungus Trichophyton?
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During which stage of bacteriophage replication does the viral DNA enter the host?
During which stage of bacteriophage replication does the viral DNA enter the host?
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What distinguishes virulence from pathogenicity?
What distinguishes virulence from pathogenicity?
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Which of the following correctly describes the behavior of opportunistic pathogens?
Which of the following correctly describes the behavior of opportunistic pathogens?
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Which stage of pathogenesis involves the pathogen evading the host immune response?
Which stage of pathogenesis involves the pathogen evading the host immune response?
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What is a primary characteristic of systemic infections?
What is a primary characteristic of systemic infections?
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Which of these virulence factors is specifically related to enhancing pathogen penetration during invasion?
Which of these virulence factors is specifically related to enhancing pathogen penetration during invasion?
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How do exotoxins differ from endotoxins?
How do exotoxins differ from endotoxins?
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Which process allows a pathogen to remain alive and divide within a host's phagosome?
Which process allows a pathogen to remain alive and divide within a host's phagosome?
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What role does hyaluronidase play in pathogen invasion?
What role does hyaluronidase play in pathogen invasion?
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Which of these situations exemplifies a secondary infection?
Which of these situations exemplifies a secondary infection?
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Study Notes
Fungal Characteristics and Classification
- Fungi lack chlorophyll and cannot perform photosynthesis, making them heterotrophic.
- Their cell walls are composed of chitin.
- Fungi are eukaryotic, distinguishing them from prokaryotic bacteria.
- Fungal membranes contain sterols, absent in bacterial membranes.
- Fungi's cell walls lack peptidoglycans, a component found in bacterial walls.
Fungal Forms and Structure
- Fungi exist in two forms: mold and yeast.
- Mold is multicellular, aerobic, and reproduces by forming spores.
- Yeast is unicellular, and is a facultative anaerobe. It reproduces both sexually and asexually (budding, transverse division).
- Hyphae are filaments that absorb nutrients, and mycelia are a collection of hyphae.
- Septate hyphae have walls (septa) between cells; non-septate hyphae do not.
Fungal Nutrition
- Fungi can obtain carbon in three ways:
- Saprotrophs decompose dead organic matter.
- Parasites feed on living hosts.
- Symbionts live with other organisms like algae.
- Mycorrhizae are symbiotic associations between fungi and plant roots.
- Lichens are symbiotic associations of fungi and algae.
Fungal Reproduction
- Fungi reproduce asexually through spore formation from hyphae, resulting in identical offspring. This is a faster process.
- Sexual reproduction involves the fusion of nuclei from two mating strains, producing genetic variation. This is less common than asexual reproduction.
Fungal Phyla
- Chytridiomycota: Non-septate, oldest, simplest, aquatic fungi, one class- chytrids.
- Glomeromycota: Non-septate, obligate symbionts forming endomycorrhizae (live in roots of 80% of plants).
- Zygomycota: Non-septate, saprotrophic/parasitic, key members in food science and crop pathogens; reproduce sexually by zygospores and asexually by sporangiospores.
- Ascomycota: Septate, largest phylum (75%), involved in food production, disease, and symbiotic relationships; reproduce asexually by conidiospores and sexually by ascospores.
- Basidiomycota: Septate, characterized by visible fruiting bodies (e.g., mushrooms); involved in symbiotic, saprotrophic, and parasitic relationships; reproduce asexually by conidiospores and sexually by basidiospores.
- Microsporidia: Non-septate, obligate intracellular parasites; use a polar tubule for host cell entry.
Fungal Diseases
- Ergotism: Middle Ages European disease, used to induce abortions.
- Histoplasmosis: "Summer flu", lower respiratory infection caused by Histoplasma capsulatum (inhalation of spores in soil, chicken coops, bat caves).
- Dermatophytosis (Ringworm): Fungal disease of hair, skin, and nails; caused by Trichophyton (nails) and Microsporum (skin/scalp).
- Candidiasis (Thrush and Yeast Infection): Caused by Candida albicans; includes vulvovaginitis (yeast infection) and thrush (oral infection).
- Coccidioidomycosis: "Valley fever", caused by Coccidioides immitis and C. posadasii (inhalation of dust particles with fungal spores).
Acellular Pathogens (Viruses)
- Viruses are non-living, infectious agents composed of nucleic acid (DNA or RNA) surrounded by a protein capsid.
- Capsid forms can be helical, icosahedral, or complex.
- Host range refers to the organisms a virus can infect, with tissue specificity within those organisms.
Bacteriophage Replication
- Attachment, penetration, biosynthesis, maturation, and lysis are the steps of bacteriophage replication.
- Bacteriophages utilize the host's machinery for biosynthesis.
- Virulent phages undergo the lytic cycle; temperate phages enter the lysogenic cycle, becoming part of the host's chromosome.
- Stress can cause a temperate phage to switch to the lytic cycle.
Animal Virus Replication
- Animal virus replication differs from bacteriophage replication.
- Uncoating releases viral nucleic acid from the capsid into the host cell cytoplasm.
- Enveloped viruses penetrate by fusion with the host's plasma membrane, while non-enveloped viruses enter via endocytosis.
- +ssRNA viruses directly use ribosomes for protein synthesis; -ssRNA viruses use their RNA as a template for +ssRNA synthesis.
- Enveloped viruses release by fusing with plasma membrane; some do "budding."
Retroviruses
- Retroviruses are RNA viruses that use reverse transcriptase to produce DNA from their RNA.
Viral Growth Curve
- Inoculation, eclipse, burst are steps of viral growth curve
- Burst size is maximum number of virions produced per bacterium.
Cultivation of Viruses
- Animal viruses are cultivated in fertilized chicken eggs (various sites) and/or cell cultures.
- Cell cultures can be primary (limited life span, contact inhibition), secondary (from primary), or continuous cell lines (derived from tumors, indefinite life span, no contact inhibition).
- Bacteriophages are cultivated on a bacterial lawn, forming plaques.
Detecting Viruses
- Scientists detect viruses by cytopathic effects, such as syncytia formation or cell inclusions.
Viroids and Virusoids
- Viroids are non-infectious single-stranded RNA that cause plant diseases requiring a host for replication; they don't encode proteins.
- Virusoids are infectious single-stranded RNA that require a helper virus to replicate.
Prions
- Prions are infectious self-replicating proteins causing diseases.
- Two types are PrPc (normal) and PrPsc (abnormal, misfolded, disease-causing).
Prion Disease Transmission
- PrPSC converts normal PrPc to PrPSC causing the accumulation.
Antiviral Drugs
- Antiviral drugs target various stages of viral replication.
Microbial Mechanisms of Pathogenicity
- Infection is the multiplication of a microbe in a host.
- Disease is an altered state of health.
- Signs are measurable indicators of disease (e.g., vital signs); symptoms are changes in body function (e.g., pain, nausea); syndromes are collections of signs/symptoms.
- Infectious diseases are caused by pathogens; non-infectious diseases are not.
- Communicable diseases spread between people.
- Iatrogenic diseases are contracted from medical procedures.
- Nosocomial diseases are acquired in hospitals.
- Zoonotic diseases are transmitted from animals to humans.
Disease Periods
- Incubation, prodromal, acute, decline, and convalescence.
Disease Types
- Acute diseases develop, peak, and resolve quickly.
- Chronic diseases progress slowly and persist for an extended period.
Pathogenicity and Virulence
- Pathogenicity is a microbe's ability to cause disease.
- Virulence is the degree of pathogenicity.
Primary vs. Opportunistic Pathogens
- Primary pathogens cause disease in healthy hosts; opportunistic pathogens cause disease in compromised hosts.
Stages of Pathogenesis
- Exposure, adhesion, invasion, infection, and exit.
Portals of Entry/Exit
- Portals range from eyes, nose, mouth, broken skin and insect bites, anus or urethra.
Microbial Invasion Mechanisms
- Mechanisms to invade include biofilm formation, enzymes (like coagulase, streptokinase, hyaluronidase, collagenase), and toxins.
Infection Classifications
- Local, focal, and systemic.
Primary vs. Secondary Infections
- Primary infections occur in healthy individuals; secondary infections occur in individuals weakened by a primary infection.
Antigenic Variation
- Pathogens alter surface proteins to evade host defenses by Antigenic variation by mutating spike proteins.
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Description
This quiz covers essential characteristics and classifications of fungi, discussing their unique traits such as eukaryotic structure, forms, and nutritional methods. It delves into the differences between molds and yeasts, their structural components, and reproductive processes. Test your knowledge on the fascinating world of fungi!
