Microbiology Ch 12 - The Eukaryotes: Fungi, Algae, Protozoa, and Helminths

C. Yeast is unicellular, while mold is multicellular.
What is the key difference between yeast and mold?

A. Yeast have cellulose cell walls, while mold has chitin cell walls.
B. Yeast is colonial, while mold is multicellular.
C. Yeast is unicellular, while mold is multicellular.
D. Yeast is a fungus, while mold is an alga.

D. Place the sample in a clear container filled with media containing no sugars, and leave it in a sunny window. After a few weeks, look for growth of the organism.
You are given an unknown, pure sample of a eukaryotic organism. Which of the following tests would allow you to determine if the sample contains algae?

A. Inject the organism into a lab animal. If it does not cause disease, it is an alga.
B. Determine if the organism is unicellular by microscopy. If it is unicellular, it is an alga.
C. Perform a biochemical test for the presence of chitin.
D. Place the sample in a clear container filled with media containing no sugars, and leave it in a sunny window. After a few weeks, look for growth of the organism.

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C. a chemical that inhibits the formation of cell walls
Which of the following new chemicals would NOT be effective against Giardia?

A. a chemical that inhibits the Krebs cycle
B. a chemical that inhibits formation of the membrane around the nucleus
C. a chemical that inhibits the formation of cell walls
D. a chemical that inhibits cell division

C. Apicomplexa

Apicomplexa contains many species that cause disease, including the Plasmodium species that cause Malaria.

Which phylum of protozoa contains organisms that are nonmotile obligate intracellular parasites? (Hint: They cause a well-known tropical disease.)

A. Amoebozoa
B. ciliates
C. Apicomplexa
D. Euglenozoa

C. mosquitoes
Dengue fever is transmitted by which of the following?

A. mites and ticks
B. fleas
C. mosquitoes
D. sucking lice

A. Karyogamy refers to a part of the sexual reproduction cycle in which two haploid nuclei fuse to form a diploid zygote.
Which of the following statements about fungi is true?

A. Karyogamy refers to a part of the sexual reproduction cycle in which two haploid nuclei fuse to form a diploid zygote.
B. Conidiospores are spores that are enclosed in a specialized sac-like structure.
C. Most fungi reproduce only asexually.
D. Fungi are usually identified using biochemical tests.

B. algae; paralytic shellfish poisoning (PSP)

Dinoflagellates are a type of unicellular algae. During red tide, high levels of a neurotoxin produced by Alexandrium (a dinoflagellate) are found in shellfish. Consumption of these shellfish leads to a foodborne disease called paralytic shellfish poisoning.

Dinoflagellates are a type of unicellular __________. One genus of dinoflagellates is responsible for a foodborne disease called __________.

A. protozoa; dysentery
B. algae; paralytic shellfish poisoning (PSP)
C. fungus; potato blight
D. tapeworm; cysticercosis

A. When conditions become harsh, some protozoa can form a protective capsule, which is called a cyst.
Which of the following statements about protozoa is true?

A. When conditions become harsh, some protozoa can form a protective capsule, which is called a cyst.
B. Some protozoa reproduce by schizogony, a process that is virtually identical to the budding process that happens in some yeast.
C. Most protozoa are photosynthetic.
D. All protozoa can undergo sexual reproduction.

B. Helminths usually possess specialized organ systems, including circulatory, nervous, and reproductive systems.
Which statement regarding helminths is true?

A. They are always dioecious, which means that one individual has both male and female reproductive organs.
B. Helminths usually possess specialized organ systems, including circulatory, nervous, and reproductive systems.
C. They are unicellular.
D. The life cycle of helminths is always very simple, and they usually infect only one host.

A. It has an undulating membrane, infects the vagina, and is frequently transmitted by sexual contact.
Trichomonas vaginalis can be distinguished from other parasitic protozoa by which of the characteristics listed below?

A. It has an undulating membrane, infects the vagina, and is frequently transmitted by sexual contact.
B. It is usually found in drinking water and is associated with fecal contamination.
C. It is a photosynthetic organism that lives in fresh water.
D. It infects Anopheles mosquitoes and can be transmitted by a bite.

D. Taenia saginata; tapeworm
Humans are the definitive host for __________, which is a type of __________.

A. Taenia solium; roundworm
B. Echinococcus granulosus; tapeworm
C. Plasmodium; cestode
D. Taenia saginata; tapeworm

D. Plasmodium species

The life cycle of Plasmodium species requires two hosts, one of which is a mosquito.

Which of the following organisms requires an additional nonhuman host to complete its life cycle?

A. Necator americanus
B. Ascaris lumbricoides
C. Enterobius vermicularis
D. Plasmodium species

A. cutaneous mycoses

Dermatophytes (Greek for “skin plants”) is a common label for a group of three types of fungi that cause skin disease in humans and other animals.

The term dermatophyte is typically used for fungi that cause which of the following?

A. cutaneous mycoses
B. systemic mycoses
C. opportunistic infections
D. subcutaneous mycoses

B. dimorphic fungus.
In mid-December, a woman with insulin-dependent diabetes who had been on prednisone fell and received an abrasion on the dorsal side of her right hand. She was placed on penicillin. By the end of January, the ulcer had not healed, and she was referred to a plastic surgeon. On January 30, a swab of the wound was cultured at 35°C on blood agar. On the same day, a smear was made for Gram staining. The Gram stain showed large (10 µm) cells. Brownish, waxy colonies grew on the blood agar. Slide cultures set up on February 1 and incubated at 25°C showed septate hyphae and single conidia. The most likely cause of the infection is a

A. gram-negative bacterium.
B. dimorphic fungus.
C. parasitic alga.
D. yeast.
E. protozoan.

B. fungus.
Ringworm is caused by a(n)

A. nematode.
B. fungus.
C. protozoan.
D. cestode.
E. trematode.

A. Candida albicans.
Yeast infections are caused by

A. Candida albicans.
B. Aspergillus.
C. Penicillium.
D. Histoplasma.
E. Saccharomyces cerevisiae.

B. Lichens are very tolerant to pollution.
Which of the following statements regarding lichens is FALSE?

A. The fungal partner provides a means of attachment and protects the algal partner from desiccation.
B. Lichens are very tolerant to pollution.
C. Lichens represent a mutualistic relationship between a fungus and an alga.
D. The algal partner produces carbohydrates that are absorbed by the fungal partner.
E. Lichens are often the first life form to colonize rock or soil.

D. All are unicellular.
Which of the following statements about algae is FALSE?

A. They produce oxygen from hydrolysis of water.
B. They use CO2 as their carbon source.
C. Some are capable of sexual reproduction.
D. All are unicellular.
E. They use light as their energy source.

E. they are classified as plants.
All of the following are characteristic of algae EXCEPT

A. most are photoautotrophs.
B. some produce harmful toxins.
C. they may be unicellular or multicellular.
D. they mostly live in aquatic habitats.
E. they are classified as plants.

True
Some species of dinoflagellates produce neurotoxins that cause fish kills and red tides.

True
False

C. lack mitochondria.
Giardia and Trichomonas are unusual eukaryotes because they

A. lack nuclei.
B. are motile.
C. lack mitochondria.
D. do not produce cysts.
E. do produce cysts.

D. eliminate Anopheles
Which of the following is the most effective control for malaria?

A. eliminate the intermediate host
B. vaccination
C. treating patients
D. eliminate Anopheles
E. None of these is an effective control.

B. Cryptosporidium
You see acid-fast oocysts in a fecal sample from a patient who has diarrhea. What is the MOST likely cause?

A. Giardia
B. Cryptosporidium
C. diatoms
D. Entamoeba
E. Taenia

C. plasmodial slime mold.
In the microscope, you observe multinucleated amoeboid cells with sporangia that form spores. This is a(n)

A. Euglenozoa.
B. cellular slime mold.
C. plasmodial slime mold.
D. tapeworm.
E. ascomycete.

B. they distribute nutrients by cytoplasmic streaming.
The cells of plasmodial slime molds can grow to several centimeters in diameter because

A. they form spores.
B. they distribute nutrients by cytoplasmic streaming.
C. they have a mouth to ingest nutrients.
D. they have organelles.
E. the large surface can absorb nutrients.

True
Both the cellular slime molds and the plasmodial slime molds are members of the phylum Amoebozoa.

True
False

D. All are parasites.
Which of the following statements about helminths is FALSE?

A. They are heterotrophic.
B. Some have male and female reproductive organs in one animal.
C. They are multicellular animals.
D. All are parasites.
E. They have eukaryotic cells.

C. reproductive system
Which of the following tends to be more complex in a parasitic helminth than in free-living helminths?

A. digestive system
B. nervous system
C. reproductive system
D. digestive and nervous systems
E. digestive, reproductive, and nervous systems

C. gastrointestinal route.
Helminthic diseases are usually transmitted to humans by

A. aerosols.
B. respiratory route.
C. gastrointestinal route.
D. vectors.
E. genitourinary route.

A. humans are the definitive host and crayfish are the intermediate host.
Three weeks after a river rafting trip, three family members experienced symptoms of coughing, fever, and chest pain. During the rafting trip, the family had consumed crayfish that they caught along the river banks. An examination of the patients sputum revealed helminth eggs, and serum samples were positive for antibodies to Paragonimus. All of the family members recovered following treatment with praziquantel. In the Paragonimus life cycle,

A. humans are the definitive host and crayfish are the intermediate host.
B. both humans and crayfish are definitive hosts.
C. the crayfish are the definitive host and humans are the intermediate host.
D. the source of the infection was the river water.
both humans and crayfish are intermediate hosts.

D. cysticercus.
The encysted larva of the beef tapeworm is called a

A. redia.
B. metacercaria.
C. cercaria.
D. cysticercus.
E. proglottid.

D. adult
A definitive host harbors which stage of a parasite?

A. cyst
B. larva
C. miracidium
D. adult
E. All of the answers are correct.

D. intestinal contents
What do tapeworms eat?

A. host tissues
B. plant matter
C. intestinal bacteria
D. intestinal contents
E. red blood cells

D. mosquito – definitive host
Below are paired items referring to the heartworm Dirofilaria immitis. Which of the pairs is mismatched?

A. dog – sexual reproduction
B. dog – definitive host
C. mosquito – vector
D. mosquito – definitive host
E. None of the pairs is mismatched.

D. cooking fish before eating
The life cycle of the fish tapeworm is similar to that of the beef tapeworm. Which of the following is the most effective preventive measure?

A. wearing gloves while handling fish
B. not swimming in fish-infested waters
C. refrigerating stored fish
D. cooking fish before eating
E. salting fish before eating

D. intermediate host.
If a larva of Echinococcus granulosus is found in humans, humans are the

A. definitive host.
B. infected host.
C. reservoir.
D. intermediate host.
E. None of the answers is correct.

False
The Platyhelminthes group includes roundworms, tapeworms, and flukes.

True
False

True
Cercariae, metacercaria, redia, and sporocysts are all life cycle stages of trematodes.

True
False

False
Most cases of hookworm infection are acquired by ingestion of eggs in contaminated food or water.

True
False

E. humans are the intermediate host and mosquitoes are both the definitive host and the vector.
In the malaria parasite life cycle

A. humans are the intermediate host.
B. mosquitoes are the definitive host.
C. mosquitoes are the vector.
D. humans are the intermediate host and mosquitos are the definitive host.
E. humans are the intermediate host and mosquitoes are both the definitive host and the vector.

B. houseflies
Which of the following arthropods does NOT transmit diseases by sucking blood from a human host?

A. fleas
B. houseflies
C. mosquitoes
D. kissing bugs
E. lice

True
Arthropod vectors are blood-sucking animals such as ticks, lice, and fleas that transmit microbial pathogens.

True
False

D. Candida albicans

Diagnosis of a yeast infection usually involves patient history, observation of yeast cells via microscopy, and growth of a culture on Sabouraud dextrose agar. Differentiation between yeasts and bacteria is reliant on biochemical characteristics. Differentiation between yeasts and molds is reliant on spore type and function.

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

A. Gardnerella vaginalis
B. Trichomonas vaginalis
C. Sporothrix schenckii
D. Candida albicans

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

Tori had undergone treatment with a broad-spectrum antibiotic for her respiratory infection. Antibiotic treatment most likely affected the normal flora in the vagina, resulting in a preferential decrease in bacterial numbers. Yeasts are normal flora in the vagina, but with fewer bacteria present to antagonize their growth, the yeast cells were allowed to flourish beyond their normal levels. The increased numbers of yeast cells led to Tori’s new symptoms. She had developed a yeast infection as a secondary infection to her primary respiratory infection. A secondary infection is defined as an infection caused by an opportunistic microbe after a primary infection has weakened the host’s defenses. Yeast infections are common secondary infections after antibiotic treatment for a primary bacterial infection.

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

A. The antibiotics that treated Tori’s primary respiratory infection also removed some of her normal bacterial flora, resulting in an overgrowth of other organisms.
B. Tori’s immune system was compromised because of her respiratory infection, and this resulted in a yeast infection.
C. The initial antibiotics were not successful in clearing the respiratory infection, so the organism disseminated to the genitourinary tract.
D. Tori contracted a sexually transmitted infection that was not related to the primary respiratory infection.

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

Treatment of a yeast infection includes the application of topical ointments and the use of oral antifungal agents. Nonprescription antifungal creams are among the most commonly purchased over-the-counter medications in the United States.

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

Select all that apply.

– a single oral dose of fluconazole
– an antiviral medication, such as acyclovir
– a topical over-the-counter ointment, such as clotrimazole or miconazole
– an oral narrow-spectrum antibiotic, such as penicillin G

– oral thrush
– fulminating disease

Candida albicans is also the causative agent of oral thrush and fulminating disease. Infants are prone to thrush because they come in contact with the yeast as part of mom’s normal flora when nursing. Fulminating disease, which most often afflicts immunosuppressed individuals, results when the yeast enters the bloodstream and travels throughout the entire body, resulting in a systemic infection. Individuals suffering from AIDS are susceptible to this type of infection.

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

Select all that apply.

– genital warts
– oral thrush
– fulminating disease
– syphilis

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

One of the key similarities between a fungus and its human host is that both are eukaryotic. This makes it difficult to develop antifungal drugs, because therapeutic agents that target certain properties of the fungus (e.g., ergosterol in the membrane, DNA replication, protein synthesis) also have the potential to target the host cells. One of the keys to antimicrobial therapy is selective toxicity, which means that the agent will hinder/kill the pathogen without doing much damage to the host. The more similar the agent is to its host, the harder it is to achieve selective toxicity.

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

A. Fungal cells and human cells have a nucleus, multiple organelles, and 80S ribosomes for protein synthesis.
B. Fungal cells and human host cells both have cell walls made of cellulose.
C. Fungal cells and human cells both reproduce via budding.
D. Fungal cells and human host cells both have flagella for movement.

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

Blastoconidia and chlamydoconidia are asexual spores used for reproduction. Blastoconidia and chlamydoconidia produce cells that are identical to the parent cells, whereas sexual spores produce offspring that have characteristics of both parents. Endospores are produced by bacteria during harsh conditions.

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

A. Blastoconidida and chlamydoconidia are identical to endospores.
B. Blastoconidia and chlamydoconidia are spore structures produced by budding in yeasts, whereas bacterial endospores are produced by bacteria under extreme conditions.
C. Blastoconidia and chlamydoconidia are produced only by yeasts in extreme conditions, whereas bacterial endospores are asexual reproductive structures.
D. Blastoconidia and chlamydoconidia are male and female mating structures used for reproduction in yeasts, whereas bacterial endospores are asexual reproductive structures.

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

Yeasts use the pseudohyphae as a virulence factor to better penetrate the host’s tissues and also to evade phagocytosis. Filamentous fungi use their vegetative hyphae as a means to absorb nutrients from their environment. In optimal conditions, the vegetative hyphae will grow into a substrate to obtain food and will then support the growth of aerial hyphae, which project above the surface of the medium. These aerial hyphae are responsible for producing the reproductive spores of the fungus.

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

A. Yeasts use pseudohyphae for obtaining nutrients, whereas filamentous fungi use their vegetative hyphae to invade host tissues.
B. Yeasts use pseudohyphae as a means of obtaining nutrients, whereas filamentous fungi use vegetative hyphae as a means of reproduction.
C. Yeasts use pseudohyphae to invade host tissue, whereas filamentous fungi use their vegetative hyphae for obtaining nutrients.
D. Yeasts use pseudohyphae as a means of sexual reproduction, whereas parasitic fungi use their hyphae to invade host tissue.

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