MICR 20 - 4 Eukaryotes I: Protozoa & Fungi

What are protozoa?

Unicellular eukaryotes that lack tissues and share similarities in cell structure, nutrition, life cycle, and biochemistry.

Are protozoa prokaryotic or eukaryotic?

Eukaryotic.

Do protozoa have a cell wall?

No, protozoa lack a cell wall.

Are most protozoa unicellular or multicellular?

Unicellular.

Are protozoa autotrophic or heterotrophic?

Heterotrophic.

Why are protozoa heterotrophic?

They lack chloroplasts and obtain nutrients by engulfing other microbes and organic matter.

Where do most free-living protozoa live?

In moist habitats.

What are the two regions of protozoan cytoplasm?

Ectoplasm and endoplasm.

What structures do most protozoa use for locomotion?

Flagella, cilia, or pseudopods.

What is a trophozoite?

The motile, feeding stage of a protozoan.

What is a cyst?

A dormant stage that allows many protozoa to survive unfavorable conditions for growth and feeding.

What type of reproduction do all protozoa carry out?

Asexual reproduction by mitosis or multiple fission.

What additional type of reproduction occurs in many protozoa?

Sexual reproduction by conjugation.

What characteristics can be used to identify protozoa microscopically?

Cell shape and size, type/number/distribution of locomotor structures, special organelles or cysts, and number of nuclei.

A protozoan moves using pseudopods. Which group does it belong to?

Amoebozoa.

A protozoan moves using cilia. Which group does it belong to?

Ciliophora.

A protozoan moves using flagella. Which group does it belong to?

Euglenozoa.

A protozoan is nonmotile and an intracellular parasite with a complex life cycle. Which group does it belong to?

Apicomplexa.

Which protozoan group includes Giardia lamblia?

Excavata.

What is characteristic of Excavata in these slides?

They have no mitochondria and multiple flagella.

Where is Giardia lamblia found?

In the small intestine.

Does Trichomonas vaginalis have a cyst stage?

No.

Where does Trichomonas vaginalis infect?

The vagina and male urinary tract.

How can Trichomonas vaginalis be transmitted according to the lecture?

Sexually or by infected towels and toilets.

Which protozoan causes amoebic dysentery?

Entamoeba histolytica.

Where is Entamoeba histolytica found?

In the intestine.

Which Amoebozoa is associated with waterborne infection?

Acanthamoeba.

Which amoeba can cause brain abscesses and granulomatous amoebic encephalitis?

Balamuthia.

What is characteristic of Apicomplexa?

They are nonmotile intracellular parasites with complex life cycles.

Which Apicomplexa causes malaria?

Plasmodium.

Which Apicomplexa include Babesia, Cryptosporidium, and Cyclospora?

Apicomplexa.

What organism causes malaria?

Plasmodium.

What vector transmits Plasmodium?

Anopheles mosquito.

What happens when an infected mosquito bites a human in the Plasmodium life cycle?

Sporozoites enter the human and migrate through the bloodstream to the liver.

Where does Plasmodium undergo schizogony initially?

In liver cells.

What are produced during schizogony in the liver?

Merozoites.

What do merozoites infect?

Red blood cells.

What happens when infected red blood cells rupture?

Merozoites are released and can infect new red blood cells.

What forms develop from some merozoites in red blood cells?

Male and female gametocytes.

What happens when another mosquito bites an infected human?

It ingests the gametocytes.

Where do the gametocytes unite to form a zygote?

In the mosquito's digestive tract.

Which host is the intermediate host for Plasmodium in the lecture diagram?

Human.

Which host is the definitive host for Plasmodium in the lecture diagram?

Mosquito.

Which protozoan is the only human parasite among the ciliates listed?

Balantidium coli.

How do ciliates move?

By cilia.

What is characteristic of Euglenozoa?

They move by flagella and include photoautotrophs and chemoheterotrophs.

Which Euglenozoan has an undulating membrane and is transmitted by vectors?

Trypanosoma.

Which Euglenozoan has a flagellated form in the sand fly vector and an ovoid form in the vertebrate host?

Leishmania.

Which Euglenozoan has both flagellated and amoeboid forms and can cause meningoencephalitis?

Naegleria.

What kingdom do fungi belong to?

Kingdom Fungi.

Are fungi prokaryotic or eukaryotic?

Eukaryotic.

Are fungi autotrophic or heterotrophic?

Chemoheterotrophic.

What is mycology?

The study of fungi.

Are most fungi aerobic or anaerobic?

Most are aerobic or facultatively anaerobic.

What is the primary ecological role of most fungi?

Decomposers.

Are most fungi unicellular or multicellular?

Most are multicellular, but yeasts are unicellular.

What is a fungal thallus?

The body of a fungus.

What is a hypha?

A fungal filament.

What is a mycelium?

A mass of fungal hyphae.

What makes a pathogenic fungus dimorphic?

It can exist in different forms depending on temperature.

At what temperature are pathogenic dimorphic fungi yeast-like?

37°C.

At what temperature are pathogenic dimorphic fungi mold-like?

25°C.

What are molds?

Filamentous fungi composed of hyphae.

What are yeasts?

Unicellular, non-filamentous fungi that are usually spherical or oval.

How do fission yeasts divide?

Symmetrically or evenly.

How do budding yeasts divide?

Asymmetrically or unevenly.

What are the two major types of fungal reproduction?

Asexual and sexual reproduction.

What is one method of asexual fungal reproduction?

Simple fragmentation of hyphae.

How can fungi reproduce asexually using spores?

A single hypha can produce spores.

What happens during sexual fungal reproduction?

Nuclei from two organisms of the same species fuse to form one organism.

What is the primary method of fungal reproduction shown in the lecture?

Production of spores on reproductive hyphae.

What are sporangiospores?

Spores formed by successive cleavages within a saclike structure called a sporangium.

Where are sporangiospores initially located?

Inside a sporangium.

How are sporangiospores released?

The sporangium ruptures.

What are conidiospores (conidia)?

Free spores that are not enclosed by a spore-bearing sac.

What is one major difference between sporangiospores and conidia?

Sporangiospores are enclosed in a sporangium; conidia are not enclosed by a spore-bearing sac.

What happens before sexual spores are formed?

Two different strains fuse and form a sexual structure.

What are three types of sexual fungal spores listed in the lecture?

Zygospores, ascospores, and basidiospores.

Why are sexual spores and their spore-forming structures important?

They are one basis for fungal classification.

What is a mycosis?

A fungal disease.

Where do systemic mycoses occur?

Deep within the body.

Where do subcutaneous mycoses occur?

Beneath the skin.

What do cutaneous mycoses affect?

Hair, skin, and nails.

What are superficial mycoses?

Mycoses localized to areas such as hair shafts.

What are opportunistic mycoses?

Fungal infections caused by organisms that are normally harmless but can become pathogenic under certain conditions.

What can cause an opportunistic pathogen to become pathogenic?

A compromised immune system, broad-spectrum antibiotic treatment, serious debilitation, or trauma.

Which fungus is an important opportunistic pathogen in AIDS patients?

Pneumocystis.

What is candidiasis normally caused by?

Candida albicans.

What are two forms of candidiasis mentioned in the lecture?

Vulvovaginal candidiasis and thrush.

Which fungus is associated with bread, wine, and beer production?

Saccharomyces.

What is one negative effect of Saccharomyces?

Food spoilage.

What fungus is associated with cellulose used for juices and fabric?

Trichoderma.

What fungus causes chestnut blight?

Cryphonectria parasitica.

What fungus is associated with Taxol production?

Taxomyces.

What fungus causes Dutch elm disease?

Ceratocystis ulm.

What fungus is associated with gypsy moth control?

Entomorphaga.

What are lichens?

A mutualistic combination of an alga or cyanobacterium and a fungus.

What does the alga/cyanobacterium provide in a lichen?

It produces and secretes carbohydrates.

What does the fungus provide in a lichen?

A holdfast.