Biology: Parasites Overview

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Questions and Answers

What is a key characteristic of parasites?

They live on non-living organisms.

They can survive without water.

They do not require oxygen.

They live on living organisms. (correct)

Which material composes the cell wall of fungi?

Cellulose

Peptidoglycan

Chitin (correct)

Keratin

In what form do fungi primarily store food?

As sugars

As starch

As proteins

As lipids and glycogen (correct)

What type of pH do parasites grow best in?

Neutral pH Signup and view all the answers

Which of the following statements is true regarding the oxygen requirements of parasites?

They all require oxygen. Signup and view all the answers

What structures do fungi use for reproduction and survival in dry conditions?

Spores and conidia Signup and view all the answers

Which of the following is NOT true about spore formation in fungi?

Spores act only as metabolic structures. Signup and view all the answers

Which of the following accurately describes how yeast and molds differ?

Yeast is unicellular, while molds are multicellular. Signup and view all the answers

What type of hyphae are characterized by having numerous cross-walls?

Septate Signup and view all the answers

Which form of fungi typically exhibits a smooth and creamy growth pattern?

Yeasts Signup and view all the answers

Which pigment characteristic best describes hyaline mycelium?

Non-pigmented and transparent Signup and view all the answers

Which feature is unique to aerial hyphae compared to vegetative hyphae?

Holds the conidia Signup and view all the answers

What are the structures that reproduce yeast through budding called?

Blastoconidia Signup and view all the answers

Which description fits dimorphic fungi?

Have two distinct morphological forms Signup and view all the answers

What is the main role of vegetative mycelium?

Absorption of nutrients Signup and view all the answers

Which type of hyphae is synonymous with being aseptate?

Coenocytic Signup and view all the answers

What type of organism is associated with anthropophilic favus hyphae?

Human Signup and view all the answers

What does the term 'ectothrix' refer to in relation to fungal infections?

Infection outside the hair Signup and view all the answers

Which medium is specifically designed for testing dermatophytes?

Mycosel Signup and view all the answers

What characteristic feature is associated with the scutula in skin infections?

Crusty lesions Signup and view all the answers

What is the function of a wood's lamp in clinical observation?

To fluoresce specific fungal infections Signup and view all the answers

What type of mycoses involves tissue invasion?

Systemic mycoses Signup and view all the answers

Which statement is true regarding dermatomycoses?

They involve skin and cannot reach systemic levels. Signup and view all the answers

What is the primary characteristic of subcutaneous mycoses?

They occur under the skin. Signup and view all the answers

Which system is primarily affected by systemic mycoses?

Reticuloendothelial system Signup and view all the answers

Who is most at risk of opportunistic fungal infections?

People suffering from low immunity or other infections Signup and view all the answers

What allows opportunistic fungi to cause infections in certain individuals?

Existing low immunity Signup and view all the answers

Which of the following correctly describes systemic mycoses?

Involve multiple deep organs. Signup and view all the answers

What is a characteristic of both cutaneous mycoses and dermatomycoses?

They are limited to the skin. Signup and view all the answers

What method of transmission involves inhaling fungal spores?

Inhalation Signup and view all the answers

Which of the following is NOT a part of the fungal culture process?

Viral elimination Signup and view all the answers

What does serological testing in the fungal culture process typically assess?

Presence of antibodies Signup and view all the answers

Which of the following best describes inoculation in the context of fungal transmission?

Transmitting fungi through skin trauma Signup and view all the answers

Which term refers to the life cycle forms of fungi that produce asexual spores?

Anamorph Signup and view all the answers

Study Notes

Overview of Parasites and Fungi

Parasites live on living organisms and have a chitin-based cell wall.
They store food in the form of lipids and glycogen.
Capable of staining both gram positive and gram negative.
Require water and oxygen for growth; not obligate anaerobes.
Optimal growth occurs at neutral pH and in moist conditions.
Reproduce through spores and conidia; spore for survival, conidia for reproduction.

Classification of Fungi

Fungi exist in two main forms: yeasts and molds.
Yeasts are smooth, creamy, or mucoid, reproduce by budding, resulting in blastoconidia.
Molds exhibit filamentous growth due to mycelial structures.

Types of Hyphae

Septate Hyphae: Contain numerous cross-walls.
Coenocytic (Aseptate) Hyphae: Have few or no cross-walls.
Mycelium: A mass of branching hyphae that functions in nutrient absorption.
Aerial Hyphae: Filamentous, responsible for producing conidia.
Vegetative Hyphae: Responsible for nutrient absorption from media.

Morphological Characteristics of Hyphae

Hyaline Hyphae: Non-pigmented, clear, transparent, will appear blue when stained.
Dematiaceous Hyphae: Pigmented, exhibiting black or brown colors without stain.

Types of Vegetative Hyphae

Antler hyphae resemble antlers.
Nodular hyphae appear knot-like.
Racquet hyphae bear a resemblance to racquets.

Modes of Transmission

Fungal spores can be produced asexually or both sexually and asexually.
Common transmission methods include inhalation, inoculation through skin/mucous membrane, and ingestion.

Fungal Culture Process

Involves specimen collection and direct examination.
Requires selection, inoculation of media, and evaluation of growth.
Includes serological and antifungal susceptibility testing.

Classification of Mycoses

Cutaneous Mycoses/Dermatomycoses: Involve tissue invasion but do not reach systemic levels.
Subcutaneous Mycoses: Occur under the skin.
Systemic Mycoses: Involve multiple deep organs; can progress from superficial to internal organs.

Opportunistic Mycoses

Typically affect individuals with lowered immunity.
Frequently seen in patients with existing bacterial or viral infections, leading to secondary fungal infections.

Manifestations of Fungal Infections

Ectothrix: Infection occurs outside hair.
Endothrix: Infection occurs inside hair.
Wood’s Lamp: Used for diagnosis via fluorescence.
Scutula: Crusty skin lesions associated with skin infections.

Culture Techniques for Clinical Materials

Use of specialized media such as Mycosel and DTM for dermatophyte testing.
Cornmeal agar and slide culture help visualize colony morphology and characteristics.

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Description

This quiz explores the characteristics and behaviors of parasites, including their structural features and modes of food storage. Learn about the significance of chitin in their cell wall and how they interact with living organisms. Get ready to test your knowledge on this important biological topic!