FUNGI AND PROTOZOA

What are protozoa?

Eukaryotic microorganisms that are unicellular and microscopic.

What is a notable characteristic of most protozoa?

They can move independently.

Which genus of protozoa is known for both motility and photosynthesis?

Euglena.

How do most protozoa reproduce?

Asexually, although sexual reproduction has been observed in some species.

What type of respiration do most protozoa perform?

Most are aerobic, but some are anaerobic.

In what types of habitats can protozoa be found?

Most moist habitats, including freshwater, marine environments, and decaying organic matter.

What role do protozoa play in aquatic ecosystems?

They serve as zooplankton, forming the base of many food chains.

What is the size range of protozoa?

They can vary from 1 to 150 μm, with most parasitic protozoa being less than 50 μm.

What are the two forms that many protozoa alternate between?

A free-living vegetative form called a trophozoite and a resting form called a cyst.

What is the function of a protozoal cyst?

It resists harsh environmental conditions, similar to a bacterial spore.

How do protozoa obtain food?

Most are heterotrophic and obtain food particles by phagocytosis.

What are the three types of locomotor organelles in protozoa?

Flagella, cilia, and pseudopodia.

What taxonomic scheme did the Society of Protozoologists publish in 1985?

A scheme that distributed protozoa into six phyla.

Which two phyla of protozoa contain the most important species causing human disease?

Sarcomastigophora and Apicomplexa.

What was the previous classification of Dientamoeba fragilis before electron microscopy revealed its true nature?

It was thought to be an ameba and placed in the family Entamoebidae.

What is the role of contractile vacuoles in protozoa?

To remove excess water from the cell.

What is the function of food vacuoles in protozoa?

To digest nutrients ingested through phagocytosis.

What is the significance of lysosomal enzymes in protozoa?

They digest nutrients within food vacuoles.

What is the typical number of nuclei in protozoa?

Most have a single nucleus, but some have a macronucleus and one or more micronuclei.

Where are some anaerobic protozoa found?

In the human intestine and animal rumen.

What is the importance of protozoa in food webs?

They participate in many food webs as primary consumers.

What is the significance of morphology in the classification of protozoa?

It is based on observations from light, electron, and scanning microscopy.

What kingdom are all protozoal species assigned to in the Whittaker classification?

Kingdom Protista.

What is the primary basis for the classification of protozoa?

How they move.

What are the defining characteristics of Phylum Mastigophora?

Protozoa having one or more flagella, with reproduction generally occurring by fission.

Give an example of a protozoan in Phylum Mastigophora that has a single flagellum.

Trypanosoma.

What is a notable feature of flagellar motion in Mastigophora?

It tends to be jerky, allowing identification in live specimens.

What is Euglena gracilis known for?

It is a flagellated organism with chlorophyll pigments for photosynthesis, classified as both a unicellular algae and a protozoan.

What disease does Giardia lamblia cause?

Giardiasis, which leads to intestinal distress, flatulence, and abdominal distention.

What sexually transmitted disease is caused by Trichomonas vaginalis?

Trichomoniasis.

What are Trypanosomes and how are they transmitted?

Heteroxenous protozoa requiring more than one host, transmitted via blood-feeding invertebrates/insects.

What disease is caused by Trypanosoma brucei and how is it transmitted?

Sleeping sickness, transmitted by the tse tse fly.

What disease is caused by Trypanosoma cruzi and how is it transmitted?

Chagas disease, transmitted by the kissing bug.

What is Leishmania donovani known for?

Causing kala-azar or black disease, transmitted by sand flies.

What is the movement mechanism of organisms in Phylum Sarcodina?

They move by pseudopodia.

What is the asexual reproduction method of Sarcodina?

Fission of the cell.

Name two marine groups included in Phylum Sarcodina.

Foraminiferans and radiolarians.

What disease does Entamoeba histolytica cause?

Amoebic dysentery.

What is the active stage of Entamoeba histolytica called?

Trophozoite.

What can Entamoeba gingivalis cause?

Gingivitis.

What is the significance of Entamoeba coli?

It is a harmless inhabitant of the colon.

What diseases are caused by Acanthamoeba and Naegleria fowleri?

Meningoencephalitis.

What serious condition can Acanthamoeba species cause in contact lens users?

Serious eye-threatening corneal ulcers.

What disease is primarily caused by amoebas of the genus Naegleria?

Primary amebic meningoencephalitis, which is usually fatal.

How are parasites from the genus Naegleria transmitted?

Through contaminated lens-cleaning solution.

What is the main mode of movement for protozoa in the Phylum Ciliophora?

They move by means of cilia.

What are the two types of nuclei found in Ciliophora protozoa?

Macronucleus and micronucleus.

What is one method of reproduction in the Phylum Ciliophora?

Conjugation, along with transverse binary fission.

What is Paramecium known for?

Its ability to conjugate and exchange genetic material.

What is Balantidium coli and what does it cause?

The largest protozoan parasite affecting humans, causing ulcer formation and bloody diarrhea.

What is a defining feature of the Phylum Apicomplexa?

Presence of an apical complex (polar ring/micronemes) at some stage.

What is a common characteristic of all species in the Phylum Apicomplexa?

They are all parasitic and lack means of locomotion in the adult form.

What important pathogen is associated with pneumonia in AIDS patients?

Pneumocystis carinii.

Name two diseases caused by Toxoplasma gondii.

Toxoplasmosis, particularly in immunocompromised patients.

What is the primary disease caused by Plasmodium species?

Malaria.

How many species of Plasmodium are known to infect humans?

At least 11 species.

What are the two hosts in the life cycle of Plasmodium?

A vector, usually a mosquito, and a vertebrate host.

Which genus of mosquito transmits the Plasmodium species causing malaria?

Anopheles.

What is the classification of Microsporidia?

They are spore-forming unicellular parasites now known to be fungi or closely related to fungi.

What is the typical host range for Microsporidia?

They infect a variety of animal hosts, primarily insects, crustaceans, and fish.

How many named species of Microsporidia are there approximately?

About 1500 of the more than one million estimated species.

What type of infections do Microsporidia typically cause in humans?

Opportunistic infections.

What is the significance of the contractile vacuole in Ciliophora?

It is usually present and helps in osmoregulation.

What is the life cycle stage that Apicomplexa members form?

Spores.

What is the largest protozoan parasite affecting humans?

Balantidium coli.

What is the result of Balantidium coli attacking the intestinal epithelium?

Ulcer formation leading to bloody diarrhea.

What is the estimated number of species in the fungi kingdom?

Around 1.5 million species, with about 5% formally classified.

How do fungi obtain nutrients?

By absorption of simple organic compounds.

What are the two main reproductive methods of fungi?

Fungi reproduce by both sexual and asexual means.

What is the study of fungi called?

Mycology.

What are fungal diseases referred to as?

Mycoses.

What role do fungi play in the ecosystem?

They are major decomposers of organic materials, recycling nutrients like carbon, nitrogen, and phosphorus.

What are the two major groups of fungi?

Filamentous fungi (molds) and unicellular fungi (yeasts).

What are hyphae?

Tubular, elongated, and thread-like structures that make up the body of most fungi.

What is mycelium?

A tangled mass of hyphae visible to the unaided eye.

What is the composition of the fungal cell wall?

Composed of glucans and chitin.

What is ergosterol?

A sterol found in the cell membrane of fungi.

What is the optimal pH for fungal growth?

About 5 (acidic pH).

At what temperature do most fungi grow best?

About 25°C, except for pathogens which grow at 37°C.

What type of environments do most fungi prefer?

Rich in organic matter and terrestrial environments.

What are coenocytic fungi?

Fungi whose cytoplasm passes through and among cells of the hypha without interruption by cross walls.

What are septate fungi?

Fungi that have cross walls (septa) dividing the hyphae into compartments.

What is conidia?

The spore structure of fungi.

How do yeasts differ from molds?

Yeasts are unicellular fungi with a single nucleus, while molds are filamentous.

What is the growth rate of fungi compared to bacteria?

Fungi have a slower growth rate than bacteria.

What is a dimorphic fungus?

A fungus that can switch between a yeast phase and a hyphal phase in response to environmental conditions.

Where can fungi be found?

Fungi have a worldwide distribution and can grow in a wide range of habitats, including extreme environments.

What is the significance of fungal diseases?

They can cause superficial, cutaneous, subcutaneous, systemic infections, and many plant diseases.

What is the size range of hyphae?

Hyphae are cylindrical, thread-like structures 2-10 µm in diameter and can be several centimeters in length.

What is the process by which new hyphae are formed?

By branching from existing hyphae or bifurcating tips.

What are yeasts?

Microscopic, unicellular fungi with a single nucleus and eukaryotic organelles that reproduce asexually by budding.

What is the process of budding in yeasts?

A new cell forms at the surface of the original cell, enlarges, and then breaks free to assume an independent existence.

What are dimorphic fungi?

Fungi that can shift from the yeast form to the mold form and vice versa.

How do fungal pathogens typically exist in the body?

Many exist in the yeast form but revert to the mold form in the laboratory when cultivated.

What are the two main types of spores produced by fungi?

Asexual spores and sexual spores.

What are conidia?

A type of asexual spore that is free and unprotected at the tips of hyphae.

What are sporangiospores?

A type of asexual spore formed within a sac.

Why are fungal spores important?

They are unique in shape, color, and size, aiding in the identification and classification of fungi.

What is the significance of a single spore in fungi?

A single spore can germinate and reestablish the entire mycelium.

What is asexual reproduction in fungi?

Occurs when spores form by mitosis, allowing more rapid dispersal than sexual reproduction.