Pre-Lecture Quiz 10

Although many people along the Mississippi, Missouri and Ohio River valleys have been exposed and test positive for histoplasmosis, most (95%) are asymptomatic. How do they clear the organism from their bodies?

cell-mediated immunity

Which topical medication would likely be recommended for use in this case?

clotrimazole cream

Some scientists want to study cellular interactions in colonial organisms; they could use ___________ as a research organism.

colonial algae

How can this disease best be categorized?

contagious and chronic

Fungi exist as either unicellular yeasts or _____.

filamentous molds

Which of the following medications is typically used for superficial candidiasis in AIDS patients?

fluconazole

Diploid cells undergo meiosis producing _____.

four haploid nuclei

A dikaryon differs from a diploid cell in that the dikaryon _____.

has two separate nuclei

If the hyphae of a fungus are septate, this means they _____.

have crosswalls separating the cells

What would be the most effective oral agent to use for treating the condition depicted in this case?

terbinafine tablets

Which stage of sexual reproduction involves the fusion of hyphae tips from opposite mating types to produce cells with two separate nuclei?

the dikaryotic stage

In which population might we observe a higher incidence of thrush?

the elderly

Which of the following would NOT be a risk factor associated with the development of histoplasmosis in people?

traveling to China

In which part of the body would candidiasis present as curd-like?

vagina

Which of the following factors would NOT contribute to the development of severe dermatomycoses?

wearing sandals

Unicellular, spherical fungi are called

yeasts

Which of the following statements best describes why the treatment for Tori's fungal infection may result in side effects to her own cells?

Fungal cells and human cells have a nucleus, multiple organelles, and 80S ribosomes for protein synthesis.

Based on the microscopic image in Part B, the organism appears to belong to the division __________.

Zygomycota

A mushroom is an example of _____, which is the reproductive organ of a mold.

a fruiting body

Which of the following pieces of equipment could be used to make a product that would transmit Zygomycota spores via inhalation?

a nasal spray bottling machine

Which of the following could Tori's physician choose as a treatment for her yeast infection?

a topical over-the-counter ointment, such as clotrimazole or miconazole a single oral dose of fluconazole

What antifungal drug is commonly used to treat systemic mycoses of pathogenic fungi?

amphotericin B

What is the "gold standard" for treatment of histoplasmosis?

amphotericin B

What percent of people harbor Candida naturally in their body without showing any signs or symptoms?

40-80%

How do blastoconidia and chlamydoconidia produced by yeast differ from bacterial endospores?

Blastoconidia and chlamydoconidia are spore structures produced by budding in yeasts, whereas bacterial endospores are produced by bacteria under extreme conditions.

Which opportunistic fungus is characterized by pseudohyphae?

Candida

Based on the lab results, which organism is most likely causing Tori's new symptoms?

Candida albicans

Which of the following habits might best prevent infection with Candida?

Change wet diapers often.

How are fungal and animal cytoplasmic membranes different from each other?

Fungal spores are reproductive structures, while bacterial endospores are survival structures.

What are dimorphic fungi?

Fungi that can exist in yeast form and mold form

Which of the following is multicellular, chemoheterotrophic, and has a cell wall?

Histoplasma

This disease is also known as Spelunker's Disease and Cave Disease. What is the most likely cause of Nate's illness?

Histoplasma capsulatum

What is the most likely cause of this man's current health problems?

Histoplasma capsulatum

How likely is it that other scouts were infected during the caving camp out?

It is highly likely that 90% or more of the scouts will show evidence of infection (antibody formation). Only a small percentage of these will get sick.

Is it critical to determine the fungal agent or agents contributing to this case? Why or why not?

No. The treatment would be the same.

Which of the following best explains why Tori developed a new series of symptoms?

The antibiotics that treated Tori's primary respiratory infection also removed some of her normal bacterial flora, resulting in an overgrowth of other organisms.

What does it mean for a cell to be haploid?

The cell has only one set of chromosomes.

Sexual reproduction often involves two haploid sex cells or gametes. A smaller, mobile, male gamete typically fuses with a larger, nonmobile, female gamete. Why are the sex cells of fungi called + and -, instead of male and female?

The haploid sex cells of fungi are virtually indistinguishable from one another.

When viewed through a microscope, some fungi with branched hyphae look somewhat like plants. Why are fungi not plants?

They lack chloroplasts and therefore cannot perform photosynthesis.

How do humans acquire this disease?

This disease is most commonly acquired by inhalation.

How do pseudohyphae in yeasts differ from vegetative hyphae in filamentous fungi?

Yeasts use pseudohyphae to invade host tissue, whereas filamentous fungi use their vegetative hyphae for obtaining nutrients.

What tools would the doctor use to diagnose this disease?

identification of the budding yeast in KOH-prepared samples of skin scrapings or sputum from the patient

What is the most common portal of infection for true fungal pathogens that cause systemic mycoses?

inhalation

What was the source of the infection?

inhalation of spores from the bat guano

What is the name of the antifungal drug that Nate is taking?

ketoconazole

Fungi that cause disease only in people with poor immunity or disrupted microbiomes are called

opportunistic fungi.

Which of the following infections are also caused by C. albicans?

oral thrush fulminating disease

Which structure is characteristic of Candida?

pseudohyphae

A microbiologist is making agar plates in which to grow bacteria. She can get the agar from

red algae