Microbio Lab - Quiz 2 Review

PBSC - Dr. John Destefano - Fall 2026

An absorptive heterotroph obtains nutrients by:

Ingesting nutrients and digesting them outside the organism

Dimorphic fungi have:

Both mold and yeast life-cycle stages

Hyphae are:

Long cells that make up the bodies of filamentous fungi

Which description best matches a yeast?

Unicellular and usually round or oval

A mycelium is best defined as:

A mass of hyphae visible to the naked eye

Aerial hyphae are primarily involved in:

Reproduction

Budding yeast cells divide:

Unevenly, producing a bud

Fission yeasts divide:

Evenly

The lecture identifies yeastlike growth at 37°C and moldlike growth at 25°C as a feature of dimorphic fungi.

True

A sporangiospore is:

Enclosed in a sac

Arthroconidia are formed by:

Fragmentation of septate hyphae

Blastoconidia are:

Buds of the parent cell

Karyogamy is the process in which:

The + and - nuclei fuse to form a diploid zygote

Meiosis in the fungal sexual cycle produces:

Haploid nuclei/spores

An ascus is best described as a:

Sac associated with ascomycetes

Ascomycetes are associated with the production of:

Ascospores from an ascus

Basidia undergo meiosis to produce:

Four basidiospores

Candida albicans (ascomycete) can produce pseudohyphae, which may increase virulence by:

Making phagocytosis more difficult for macrophages

Saccharomyces cerevisiae is associated with the production of:

Bread, wine, and beer

Rhizopus is described as producing a characteristic:

Salt-and-pepper appearance as the mycelium darkens

Aspergillus niger produces:

Black colonies

Penicillium is commercially important in:

Cheese fermentation

Mannitol Salt Agar (MSA) is described as a medium used to:

Selectively isolate and identify bacteria

A smear is:

A thin film of material containing microorganisms spread over a slide

Negative staining colors:

Stains the background rather than the cell

Acid-fast bacteria resist decolorization because their cell walls contain:

Mycolic acids

The counterstain stain listed for the acid-fast stain is:

Methylene blue

The primary stain used in the acid-fast procedure is:

Carbolfuchsin red

In the Ziehl-Nelsen procedure, steam is used primarily to:

Enhance penetration of carbolfuchsin into the waxy wall

In the Ziehl–Neelsen method, acid-alcohol is used to:

Decolorize

The Kinyoun method uses a more concentrated/lipid-soluble carbolfuchsin preparation so that it can:

Penetrate without heat

Acid-fast staining is generally used when:

There is high suspicion of acid-fast organisms

A capsule is best described as:

A gelatinous covering that does not accept most dyes.

Capsules contribute to virulence by:

Preventing phagocytosis

In a capsule stain using nigrosin or Congo red, the capsule appears as:

An unstained halo around the cell

In a capsule stain, the capsule typically appears as:

A halo around the cell

After endospore staining, spores appear:

Green within red or pink cells

The primary stain in the Schaeffer–Fulton endospore method is:

Malachite green

Endospores are described as:

Dormant, resistant structures formed inside some cells

Endospores are resistant to desiccation, heat, chemicals, and radiation.

True

Germination is the process in which an endospore returns to the vegetative state.

True

Germination refers to:

An endospore returning to the vegetative state

Sporulation refers to:

Endospore formation

The central goal of aseptic transfer is to avoid contamination of:

The original source, sterile medium, and surroundings

The primary purpose of aseptic transfer is to:

Avoid contamination of the original source, sterile medium, and surroundings

Which instrument is listed as being sterilized before use?

Inoculating loop or needle

Which instrument is used to sterilize an inoculating loop before and after transfer?

Micro-incinerator or Bunsen burner

The culture tube should be held at an angle to help avoid airborne contamination.

True

The lecture emphasizes being organized, labeling plates, taking your time, and using instruments as intended.

True

The lecture instructs students to sterilize the loop for approximately:

4–5 seconds, until glowing red

The lid of the Petri dish is used as:

A shield

The loop should be sterilized in the incinerator for approximately:

4–5 seconds, until glowing red

The slide recommends holding the culture tube in the dominant hand while uncapping it with the loop hand.

False

The slide recommends working close to the heat source during aseptic transfer.

True

The top of the culture tube is flamed three times because:

Air expands when heated, reducing contamination chances

When opening a culture tube during aseptic transfer, the student should:

Move the tube, not the loop, to reduce aerosol production

Which practice is specifically recommended to reduce contamination during transfer?

Hold the open tube at an angle, use the dish lid as a shield, and work close to the heat source

Which statement best describes fungi as presented in the lecture?

They are nonmotile eukaryotes that digest nutrients externally and absorb them

The primary polysaccharide identified in fungal cell walls is:

Chitin

The asexual reproduction method specifically associated with many yeasts is:

Budding

Which pairing is correct?

Yeast—unicellular; mold—filamentous

Hyphae with crosswalls are described as:

Septate

Which hyphae primarily obtain nutrients?

Vegetative hyphae

The slide associates yeastlike growth with approximately:

37°C

During fungal sexual reproduction, plasmogamy refers to:

Fusion of cytoplasm while the nuclei remain separate initially

Karyogamy is the process in which:

The + and − nuclei fuse to form a diploid zygote

Which sequence correctly lists the three phases emphasized for sexual reproduction?

Plasmogamy → karyogamy → meiosis

Which spore is not enclosed in a sac at the end of a hypha?

Conidiospore

Basidiomycota are described as club fungi because a basidium produces four basidiospores after meiosis.

True

The slide describes Zygomycota as having:

Nonseptate hyphae

Which fungal phylum is associated with Rhizopus?

Zygomycota

Candida albicans is described as:

A medically important yeast and part of normal flora

Which description best matches Rhizopus growth in the lecture?

White-grayish cottony growth that can develop a salt-and-pepper appearance

Aspergillus colonies may be green, yellow, or brown and are described as:

Granular with a white edge

Which statement about Aspergillus is consistent with the lecture?

It is ubiquitous and can cause opportunistic disease in compromised patients

Penicillium colonies are described as:

Green, powdery, radially furrowed, with a white apron

The ubiquity exercise demonstrates that microbes can be found in many environments and on many surfaces.

True

TSA (trypticase soy agar) is described as a broad-purpose medium designed to grow a broad spectrum of microbes that do not have special growth requirements.

True

Which medium is identified as a general agar medium used to isolate fungi?

SAB/Sabouraud Dextrose Agar

In a basic dye, the chromophore is a:

Cation

Which organism is specifically associated with acid-fast staining?

Mycobacterium tuberculosis

In the Kinyoun method, the primary stain is applied:

With no heat

Which statement distinguishes the Kinyoun method from the Ziehl-Nelsen method?

Kinyoun uses no heat and uses a more concentrated/lipid-soluble carbolfuchsin

The lecture states that acid-fast staining is used when there is high suspicion that acid-fast organisms are present.

True

Which organism is listed as an opportunistic acid-fast pathogen?

Nocardia

A slime layer differs from a capsule because it is:

Unorganized and loose

Which substances are listed for negative capsule staining?

Nigrosin or Congo red

In the Schaeffer-Fulton method, water is used to:

Decolorize the cells because malachite green is water-soluble

Clostridium tetani is associated with tetanus.

True

Which fungi are identified as macroscopic fungi?

All of the above

Tiny eukaryotic organisms that cannot be seen without a microscope

Microscopic fungi

Consist of hyphae filaments; filamentous; vegetative

Thallus

Fungal cells that don't have internal cross-walls—called septa, these filaments form a giant, shared space filled with cytoplasm and lots of free-floating nuclei

All of the above

Spore within a hyphal segment at the end

Chlamydoconidium

Sporangia can be involved in either asexual or sexual processes

True

In __ via spores, a single parent organism creates reproductive cells (spores) through regular cell division, or mitosis

Asexual reproduction

Gametangia acts as a protective house for gametes during sexual reproduction

True

How many gametes does it take to produce a single diploid zygote?

2

Fungi is complex and has sexual and asexual stages

True

Ascomycetes include candida and …

All of the above