Mycology

Question 1

True or False

Fungi are eukaryotic

Answer 1

True

Question 2

True or False

Fungal cells have a true nucleus with a surrounding membrane, and cell division is accompanied by mitosis or meiosis

Answer 2

True

Question 3

True or False

Fungi have rigid cell walls with chitin and glucan as major components

Answer 3

True

Question 4

True or False

Fungal cell membranes typically contain ergosterol

Answer 4

True

Question 5

Where is chitin and glucan located?

Answer 5

Cell wall

Question 6

Where is ergosterol located?

Answer 6

Cell membrane

Question 7

True or False

Fungi are heterotrophic and requrie performed organic carbon compounds for their nutrition

Answer 7

True

Question 8

What does Heterotrophic mean?

Answer 8

Lacking in chlorophyll

Question 9

What does saprphytic mean?

Answer 9

nutrients from deas and decaying matter

Question 10

True or False

Fungi secrete enzymes to break up large molecules-absorb nutrients
* can degrade cellulose and lignin (wood)
* Release CO2 and nitrogen compounsd into soil

Answer 10

True

Question 11

What is saprophytic?

Answer 11

nutrients from dead and decaying matter

Question 12

What are some of the significance of fungi?

Answer 12

• decompose dead organisms and recycle their nutrients
• help plants absorb water and minerals
• used for food
• produce antibiotics
• research tools

Question 13

What is the morphology of fungi?

Answer 13

• Two basic body shapes: molds and yeasts
• some fungi are dimorphic

Question 14

What is the difference between molds and yeast?

Answer 14

Molds
* composed of long filaments called hyphae
* multicellular
Yeasts
* small, globular, and composed of a single cell
* reproduce by mitosis or budding

Yeast reproduction under a microscope look like a tiny snowman.

Question 15

What does it mean to be dimorphic?

Answer 15

• produce both yeastlike and moldlike shapes
• change in response to environmental conditions

Question 16

How do fungi reproduce?

Answer 16

by spores

Question 17

How do fungi reproduce through spores?

Answer 17

through mitosis (asexual process)

asexual spores and spore-bearing structures are designed to ensure repid dispersal to new habitats

Question 18

How to identify yeast?

Answer 18

• colonial morphology
• microscopic morphology
• biochemical testing DNA sequencing

Question 19

Candida albicans

a yeast

Answer 19

• “feet”-like extensions commonly seen on blood agar
• terminal, thick-walled chlamydospores
• Blastoconidia clustered at septa

Question 20

Cryptococcus neoformans

a yeast

Answer 20

• cream-colored, mucoid colonies
• direct India Ink wet mount of CSF

Question 21

Hyphae

Answer 21

• rigid cell wall
• increases in length b/c of apical growth with mitotic cell division
• in higher fungi, hyphae are divided into cells by the development of cross-walls (septa)

Question 22

structure of hyphae

Answer 22

• looks like a tree branch
• the base of the branch is the septum
• apical growth is straight up
• hyphae are the little branches

Question 23

Mycelium morphology

Answer 23

Vegetative
* penetrates into the medium to absorb nutrients
Aerial
* produces spores (conidia), pigmentation, texture and topography

Question 24

What is the taxonomy and classification of fungi?

Answer 24

* Division Chytridiomycota * Division Zygomycota **+** * Division Ascomycota **+** * Division Basidiomysota **+** | **+** contains species pathogenic to humans

Question 25

What are clinical groupings for fungal infections?

Answer 25

* Cutaneous Mycoses * Subcutaneous Mycoses * Opportunistic Systemic Mycoses * Dimorphic Systemic Mycoses

Question 26

What is cutaneous mycoses?

Answer 26

* Superficial fungal infections of the skin, hair or nails * No living tissue invaded * Pathological changes are elicited due to presence of the infectious agent and its metabolic products. ## Footnote ringworm

Question 27

What is the causative organisms of Dermatophytosis? | cutaneous mycoses ## Footnote Ringworm of the scalp, skin & nails

Answer 27

Dermatophytes (Microsporum, Trichophyton, Epidermiphyton)

Question 28

What is the causative organisms of Candidiasis? | Cutaneous Mycoses ## Footnote skin, mucous membranes & nails

Answer 28

Candida albicans and related species

Question 29

What are subcutaneous mycoses?

Answer 29

* Chronic localized infections of the skin and subcutaneous tissue following the traumatic implantation of the etiologic agent * Causative fungi are soil saprophytes. * Ability to adapt to the tissue environment and elicit disease is extremely variable. ## Footnote rose gardeners disease

Question 30

What are opportunistic systemic mycoses?

Answer 30

* Fungal infections which occur in debilitated patients whose normal defense mechanisms are impaired * Involve fungi with a very low inherent virulence * Increased incidence parallels more aggressive cancer & post transplantation chemotherapy and the emergence of AIDS

Question 31

What are the pigmentation of molds?

Answer 31

* dematiaceous * hyaline

Question 32

What are dimorphic systemic mycoses?

Answer 32

* Fungal infections caused by dimorphic pathogens which can overcome the physiological and cellular defenses of the normal human host by changing their morphological form * Environmental form – filamentous or hyphal * Tissue form – yeast or yeast like * Primary site of infection – pulmonary * Geographically restricted