Chapter 20: The Fungi

Question 1

Fungi are _____ cells, which lack _____, so they cannot generate energy through photosynthesis.

Answer 1

eukaryotic

chlorophyll

(p. 196)

Question 2

Fungi require an _____ environment.

Answer 2

aerobic (p. 196)

Question 3

Yeast are a _____ growth form of fungi. These cells can appear spherical to ellipsoidal. Yeast reproduce by _____. When buds do not separate, they can form long chains of yeast cells, which are called ______. Yeast reproduce at a _____ rate than bacteria.

Answer 3

unicellular

budding

pseudohyphae

slower

Question 4

What are saprophytes?

Answer 4

fungi that live in and utilize organic matter (soil, rotten vegetation) as an energy source (p. 196)

Question 5

Dimorphic fungi can grow as either a _____ or ____, depending on environmental conditions and temperature. They usually grow as a _____ at body temperatures.

Answer 5

yeast or mold yeast (p. 196)

Question 6

What stain can be used to visualize the capsule of Cryptococcus neoformans?

Answer 6

India ink stain

Question 7

There are 3 fungi that cause systemic disease in humans. They are:

All three are _____ fungi.

Answer 7

Histoplasma capsulatum

Blastomyces dermatitidis

Coccidioides immitis

dimorphic

(p. 199)

Question 8

Histoplasma capsulatum, Blastomyces dermatitidis, and Coccidioides immitis grow as _____ forms, with spores, at 25º C on Sabouraud’s agar. At 37º C they grow as _____ cells.

Answer 8

mycelial

yeast

Question 9

What is Sabouraud’s agar?

Answer 9

Sabouraud agar is a type of agar growth medium containing peptones. It is used to cultivate dermatophytes and other types of fungi, and can also grow filamentous bacteria such as Nocardia.

It typically contains:

• 40 g/L dextrose
• 10 g/L peptone
• 20 g/L agar
• pH 5.6 – note the acidity inhibits bacterial growth

[Retrieved from Wikipedia]

Question 10

Cryptococcus neoformans is a polysaccharide encapsulated yeast (not _____) similar to the previous 3 fungi in that is is _____ into the lungs and the infection is usually _____.

It differs in that the major manifestation is not pneumonia but rather _____.

Answer 10

dimorphic; inhaled; asymptomatic

meningoencephalitis

Question 11

Roughly _ out of _ cases of crytococcal meningitis occur in immunocompromised people, and almost __% of AIDS patients will develop cryptococcosis.

Answer 11

3 out of 4

10%

Question 12

What is a polysaccharide?

Answer 12

a carbohydrate that can be decomposed by hydrolysis into two or more molecules of monosaccharides

[Retrieved from Merriam Webster]