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Questions and Answers
Which characteristic differentiates fungi from bacteria?
Which characteristic differentiates fungi from bacteria?
- Heterotrophic metabolism
- Presence of peptidoglycan in the cell wall
- Presence of sterols in the cell membrane (correct)
- Asexual spore production
A fungus that exhibits both a yeast form at 37°C and a mold form at 25°C is displaying which characteristic?
A fungus that exhibits both a yeast form at 37°C and a mold form at 25°C is displaying which characteristic?
- Achlorophyllous nature
- Dimorphism (correct)
- Saphrophytism
- Monomorphism
Which of the following is a characteristic of reproductive hyphae?
Which of the following is a characteristic of reproductive hyphae?
- Aiding in speciation
- Carrying reproductive spores (correct)
- Supporting and absorbing nutrients
- Resembling buck deer antlers
In a lab, a fungal culture is grown on Sabouraud's dextrose agar at room temperature producing a dry, filamentous colony, this indicates that the sample is likely which of the following?
In a lab, a fungal culture is grown on Sabouraud's dextrose agar at room temperature producing a dry, filamentous colony, this indicates that the sample is likely which of the following?
Calcofluor white stain is used in mycology to identify which component within fungal cells?
Calcofluor white stain is used in mycology to identify which component within fungal cells?
Which feature of the Lactophenol Cotton Blue (LPCB) stain contributes to the preservation of fungal structures for microscopic examination?
Which feature of the Lactophenol Cotton Blue (LPCB) stain contributes to the preservation of fungal structures for microscopic examination?
Which type of culture media is most likely used to screen for dermatophytes?
Which type of culture media is most likely used to screen for dermatophytes?
A yeast isolate demonstrates a unique ability to rapidly assimilate trehalose. This characteristic is most helpful in differentiating which Candida species?
A yeast isolate demonstrates a unique ability to rapidly assimilate trehalose. This characteristic is most helpful in differentiating which Candida species?
What structural component in fungi is specifically targeted by the stains used for fungal identification?
What structural component in fungi is specifically targeted by the stains used for fungal identification?
Which component of the skin does Malassezia furfur infect?
Which component of the skin does Malassezia furfur infect?
Hyperpigmentation or hypopigmentation of the skin is caused by the yeast, Malassezia furfur, and is known as what type of infection?
Hyperpigmentation or hypopigmentation of the skin is caused by the yeast, Malassezia furfur, and is known as what type of infection?
Which of the following is a characteristic of Trichophyton tonsurans?
Which of the following is a characteristic of Trichophyton tonsurans?
The Wood's lamp is a diagnostic tool for which of the following?
The Wood's lamp is a diagnostic tool for which of the following?
In systemic mycoses, what is the infectious form acquired via inhalation of spores?
In systemic mycoses, what is the infectious form acquired via inhalation of spores?
A patient is suspected of having a Cryptococcus neoformans infection. Which of the following stains is most appropriate for direct examination of a cerebrospinal fluid (CSF) sample?
A patient is suspected of having a Cryptococcus neoformans infection. Which of the following stains is most appropriate for direct examination of a cerebrospinal fluid (CSF) sample?
Which diagnostic method is used to identify types of sporulation for chromoblastomycosis?
Which diagnostic method is used to identify types of sporulation for chromoblastomycosis?
Which of the following hepatitis viruses is a DNA virus?
Which of the following hepatitis viruses is a DNA virus?
Which of the following viruses contains a double-stranded, naked, linear, and icosahedral RNA?
Which of the following viruses contains a double-stranded, naked, linear, and icosahedral RNA?
The hemagglutinin (H) antigen is critical for which function of the influenza virus?
The hemagglutinin (H) antigen is critical for which function of the influenza virus?
Picornaviridae are characterized as positive-sense, single-stranded RNA viruses and are known to cause which disease?
Picornaviridae are characterized as positive-sense, single-stranded RNA viruses and are known to cause which disease?
Flashcards
Mycology
Mycology
Study of fungi, including beneficial (e.g., alcohol production) and harmful (e.g., disease-causing) species.
Dimorphism
Dimorphism
The ability of some fungi to exist in two forms: yeast (at 37°C) and mold (at 25°C), depending on the temperature.
Mycelium/Hyphae
Mycelium/Hyphae
Branching, threadlike filaments forming the structure of fungi, can be reproductive (bearing spores) or non-reproductive (aiding in speciation).
Septate
Septate
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Aseptate
Aseptate
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Hyaline
Hyaline
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Dematiaceous
Dematiaceous
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Favic Chandeliers
Favic Chandeliers
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Nodular organs
Nodular organs
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Racquet Hyphae
Racquet Hyphae
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Spiral Hyphae
Spiral Hyphae
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Aerial mycelium
Aerial mycelium
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Vegetative mycelium
Vegetative mycelium
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Ascospores
Ascospores
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Basidiospores
Basidiospores
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Oospores
Oospores
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Zygospores
Zygospores
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Chlamydospore
Chlamydospore
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Arthrospore
Arthrospore
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Blastopore
Blastopore
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Study Notes
- This details information about Mycology and Virology
Mycology Basics
- This is the study of fungi
- Good fungi, like Mushrooms and Saccharomyces cerevisiae, are useful for alcohol and bread production
- Bad fungi cause disease
- Fungi are eukaryotic, and either aerobic or facultatively anaerobic
- Fungi are heterotrophic, obtaining nutrients from the environment by:
- Saphrophytic process where they absorb nutrients from decaying organic matter
- Fungi are decomposers
- Fungi are achlorophyllous, meaning they contain no chlorophyll, unlike plants
- Fungi can exist either as monomorphic, assuming only one form or morphology, or dimorphic, assuming two forms or morphology
- Basic fungal structures are hyphae and spores
Dimorphism
- Fungi can exist in two forms depending on the temperature:
- Yeast form at 37ºC
- Mold form at 25ºC
- The temperature the fungi is exposed to determines the form it takes
- Mold or filamentous form is the infectious stage, while the yeast or tissue form is the pathogenic stage
Structures of Fungi: Mycelium/Hyphae
- Branching, threadlike, tubular filaments can be:
- Reproductive or non-Reproductive
Reproductive Hyphae
- These carry reproductive spores
- Septate: Have crosswalls
- Aseptate (coenocytic): Lack crosswalls
- Hyaline: Transparent
- Dematiaceous: Pigmented
Non-Reproductive Hyphae: Aids in Speciation
- Favic Chandeliers: Resemble buck deer antlers, with blunt and branched hyphal ends
- Nodular organs: Knots of twisted hyphae
- Racquet Hyphae: Resemble tennis racquets placed end to end
- Spiral Hyphae: May be flat or turn like a corkscrew and are seen in older cultures
Classification of Hyphae by Location
- If aerial it functions in holding spores/conidia, extending below the agar surface
- If vegetative they support and absorb nutrients, extending above the agar
Spores - Conidia
- For reproduction
- Sexual Spores (Sexual Teleomorph Stage)
- These are perfect fungi
- Involve nuclear fusion, meiosis, and mitosis
- Ascospores: Spores contained in a sac-like structure
- Basidiospores: Involve the fusion of compatible hyphae or yeast cell with the aid of clamp connection
- Oospores: Spores resulting from the fusion of cells from two different hyphae
- Zygospores: Involve two compatible hyphae each forming an arm extending towards each other
Fungal Cell vs Bacteria Cell
- Fungi Cell
- Eukaryotic
- Cell membrane contains sterol (ergosterol)
- Cell wall contains glucans, mannans, and chitin serving as the basis of fluorescent tests or dye-based detection
- Produces sexual and asexual reproductive spores
- Limited heterotrophic, uses facultative anaerobic metabolism
- Often sensitive to polyenes, imidazole, and griseofulvin
- Bacteria Cell
- Prokaryotic
- Cell membrane lacks sterols, with the exception of Mycoplasma
- Cell wall contains peptidoglycan
- Produces spores that are for survival; termed endospores but are not for reproduction, some asexual spores
- Heterotrophic, chemoautotrophic, photoautotrophic, aerobic, facultative anaerobic, and anaerobic metabolism
- Often sensitive to penicillin, tetracycline, and aminoglycosides
Morphology: Molds/Filamentous
- Exist at room temperature (25 - 30 °C)
- Best grown at SDA (Dry colony)
- Multicellular
Morphology: Yeast/Tissue
- Exist at body temperature (37°C)
- Best grown at BHIA (Moist Colony)
- Unicellular
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