Fungi Overview Quiz

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Questions and Answers

Which of the following statements about fungi is accurate?

Some fungi are obligate aerobes.

Many fungi thrive in anaerobic environments.

All fungi are non-motile. (correct)

All fungi are capable of movement.

Which characteristic is true for the classification of fungi?

Fungi are obligate anaerobes.

Fungi lack the ability to move. (correct)

Fungi can live in extreme high temperatures.

All fungi can swim in water.

What is a correct statement regarding the respiratory categories of fungi?

Fungi can be classified into motile and non-motile groups.

Fungi are predominantly obligate anaerobes.

Fungi need oxygen to survive. (correct)

Fungi can perform photosynthesis.

Which statement about the physical characteristics of fungi is incorrect?

Most fungi are motile organisms. Signup and view all the answers

What best describes the mobility of fungi?

Fungi are entirely non-motile organisms. Signup and view all the answers

What is a common cause for subcutaneous mycoses?

Piercing trauma to the skin Signup and view all the answers

Which of the following tissues are primarily involved in subcutaneous mycoses?

Dermis, subcutaneous tissue, muscle, and fascia Signup and view all the answers

What is another name commonly associated with subcutaneous mycoses affecting the foot?

Madura foot Signup and view all the answers

What type of infections do subcutaneous mycoses represent?

Chronic infections Signup and view all the answers

Where do the fungi that cause subcutaneous mycoses typically reside?

In the soil Signup and view all the answers

What do cutaneous mycoses primarily affect?

All layers of the skin Signup and view all the answers

Which of the following is a type of cutaneous mycosis?

Tinea Signup and view all the answers

What is another term used for dermatophytosis?

Ringworm Signup and view all the answers

Which of the following is NOT a cause of cutaneous mycoses?

Bacterial infections Signup and view all the answers

Cutaneous Candidiasis is caused by which type of organism?

Yeast Signup and view all the answers

What method of reproduction do they utilize?

Asexual reproduction by budding Signup and view all the answers

What are pseudohyphae best described as?

Hyphae with constrictions, resembling a sausage-like chain Signup and view all the answers

Which of the following terms describes the appearance of pseudohyphae?

Sausage-like in a chain formation Signup and view all the answers

Which term does NOT apply to pseudohyphae?

Branching Signup and view all the answers

What characteristic distinguishes pseudohyphae from true hyphae?

Presence of constrictions Signup and view all the answers

What is the primary characteristic of mycetoma infections?

They commonly require surgical intervention. Signup and view all the answers

Which type of infections affect internal organs?

Systemic mycoses Signup and view all the answers

What treatment may be necessary for mycetoma infections?

Surgical debridement Signup and view all the answers

Which statement about systemic mycoses is false?

They are typically superficial infections. Signup and view all the answers

What is a common challenge associated with treating mycetoma?

They require longer treatment courses than typical infections. Signup and view all the answers

What is mycotoxicosis primarily caused by?

Consumption of fungal toxins Signup and view all the answers

Which organ is NOT affected by mushroom poisoning?

Pancreas Signup and view all the answers

Which of the following describes a consequence of mycotoxicosis?

Damage to liver and kidney Signup and view all the answers

What type of food is most commonly associated with causing mycotoxicosis?

Fungal toxins in mushrooms Signup and view all the answers

Which of the following is NOT a symptom of mushroom poisoning?

Memory enhancement Signup and view all the answers

Study Notes

General Mycology

Mycology is the study of fungi.
Medical mycology focuses on pathogenic fungi that cause disease.

Fungi vs. Bacteria

Size: Fungi are larger than bacteria.
Cell Type: Fungi are eukaryotic, bacteria are prokaryotic.
Mitochondria: Fungi have mitochondria, bacteria don't.
Sterols in cell membrane: Fungi contain ergosterol, the target of antifungal agents. Bacteria lack sterols in their cell membranes except those of the mycoplasma group. These have a sterol-like substance in their plasma membranes.
Cell Wall Content: Fungal cell walls are made of chitin; this is target of action against anti-fungal agents. Bacterial cell walls contain peptidoglycan.
Spores: Fungi reproduce via spores, bacteria don't (generally).
Metabolism: All fungi are heterotrophs and aerobes, while some bacteria are also heterotrophs but some are anaerobic or facultative anaerobes.

Fungal Morphology

Moulds (Filamentous Fungi):
- Multicellular filaments called hyphae
- Hyphae may be septate (cross-walls) or non-septate (no cross-walls).
- Grow by branching and tip elongation to form a mycelium
- Examples: Aspergillus, Penicillium, Dermatophytes
Yeasts:
- Unicellular (single-celled), oval or round shapes
- Reproduce asexually by budding, and can form pseudohyphae (sausage-like chains).
- Examples: Candida, Cryptococcus

Clinical Classification of Fungal Infections

Superficial mycoses: Affect the outermost keratinized layer of skin and appendages, e.g., tinea versicolor (hypopigmented/hyperpigmented areas).
Cutaneous mycoses: Affect deeper layers of skin (e.g., dermatophytes causing various ringworm infections and cutaneous candidiasis).
Subcutaneous mycoses: Chronic infections involving dermis, subcutaneous tissue, muscles, and fascia (e.g., Madura foot initiated by piercing trauma & mycetoma).
Systemic mycoses: Affect internal organs. These may be:
- True pathogens infecting healthy individuals (e.g., Histoplasma, Blastomyces)
- Opportunistic pathogens infecting individuals with weakened immune systems or compromised immune responses(e.g., Cryptococcus, Candida)
- Some conditions that raise vulnerability to these opportunistic infections include diabetes, cancer, corticosteroid therapy, cytotoxic drugs, and prolonged antibiotic therapy.

Mycotoxicosis

Caused by consuming food contaminated with fungal toxins.
Examples: mushroom poisoning, aflatoxin from Aspergillus flavus (liver damage/cancer).

Allergic Disorders

Fungal spores (e.g., Aspergillus) can act as allergens in some forms of atopy (e.g., asthma, hay fever).

Fungal Infection Diagnosis

Direct methods: Detect fungi or their antigens in specimens or isolate the organism.
Indirect methods: Detect antibodies against the suspected fungal infection in serum or via skin tests.

Antifungal Drugs

Fungi are eukaryotes, so ideally, non-toxic, systemically active drugs are limited in their range (selectivity).
Antifungal drugs target ergosterol, a component of fungal cell membranes.
Contrastingly, bacterial cell membranes contain cholesterol.
Common antifungal drugs include: Mycostatin (nystatin); azole drugs (e.g., fluconazole, ketoconazole).

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Description

Test your knowledge about fungi and their classification with this quiz. It covers various aspects including characteristics, infections, and reproduction methods of fungi. Challenge yourself and learn more about subcutaneous and cutaneous mycoses.