Protozoa Structure and Function

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Questions and Answers

What materials can the test of foraminiferans be primarily composed of?

Protein and cellulose

Chitin and sand

Calcium carbonate and silica (correct)

Silicon and silt

How do zooflagellates primarily reproduce?

Budding

Binary fission (correct)

Fragmentation

Spore formation

What structure in Euglena serves as a light-sensitive organ?

Kinetosome

Contractile vacuole

Red eyespot (stigma) (correct)

Pellicle

Which of the following statements about Testacea is true?

They may have tests made of siliceous material. Signup and view all the answers

What type of nutrition does Euglena use when kept in the dark?

Saprozoic. Signup and view all the answers

What type of locomotion do zooflagellates typically use?

Flagella Signup and view all the answers

What significant feature characterizes the colonial organism Volvox?

A cellulose cell wall with two flagella projecting. Signup and view all the answers

Which type of environment do foraminiferans predominantly inhabit?

Marine and brackish water Signup and view all the answers

What is the primary function of the pellicle in certain protozoa?

To maintain the organism's shape Signup and view all the answers

What distinguishes ectoplasm from endoplasm in protozoa?

Ectoplasm is the outer, transparent layer. Signup and view all the answers

Which of the following describes the process of pinocytosis in protozoa?

Drawing fluid through temporary openings Signup and view all the answers

Which protozoan structure is essential for osmoregulation?

Contractile vacuole Signup and view all the answers

What is the most common type of asexual reproduction in protozoa?

Binary fission Signup and view all the answers

Which of the following statements about protozoan nutrition is accurate?

All protozoa are holozoic in nature. Signup and view all the answers

The presence of which structure in the Apicomplexa aids slow movement?

Subpellicular microtubules Signup and view all the answers

In protozoans, what type of mouth is referred to as a cytosome?

A permanent opening for ingestion Signup and view all the answers

What is the primary mode of reproduction in the Coccidia during their life cycle?

Sexual reproduction involving fertilization of gametes Signup and view all the answers

What is a notable characteristic of protozoans in the Phylum Sporozoa?

They lack locomotor structures and have a tough cuticle. Signup and view all the answers

Which statement about Eimeria is correct?

Eimeria can be fatal to young fowl due to intestinal pathogenesis. Signup and view all the answers

Which class of the Phylum Sporozoa includes intracellular parasites that are significant in medicine and veterinary fields?

Class Coccidiomorpha Signup and view all the answers

How do sporozoites become infective to a new host?

When ingested after sporulation in the oocyst. Signup and view all the answers

What type of reproduction occurs during the schizogony phase of the Coccidia life cycle?

Multiple fission within the host cells. Signup and view all the answers

During the formation of the zygote in Coccidia, what encapsulates the zygote?

An oocyst Signup and view all the answers

What is the main symptom associated with Eimeria infections in animals?

Severe diarrhea or dysentery Signup and view all the answers

What was the estimated number of malaria cases in 2016?

216 million Signup and view all the answers

Which malaria species is known for not causing relapse?

P. falciparum Signup and view all the answers

How long can the prepatent period for P. falciparum be after exposure?

6 months or more Signup and view all the answers

What is the estimated number of deaths due to malaria in 2016?

445,000 Signup and view all the answers

What can cause periodic relapse of malaria over several years?

Delayed multiplication in the liver Signup and view all the answers

For which species does relapse generally occur after 3-5 years?

P. vivax Signup and view all the answers

Which malaria parasite typically does not have a long prepatent period?

P. falciparum Signup and view all the answers

What age group is particularly vulnerable to severe malaria?

Young children Signup and view all the answers

What causes Equine Piroplasmosis?

Babesia equi and Babesia caballi Signup and view all the answers

How is Leucocytozoon primarily transmitted to birds?

Simuliid and Culicoides flies Signup and view all the answers

Which disease is caused by Myxobolus pfeifferi?

Tumorous masses in freshwater fish Signup and view all the answers

What is a characteristic of Myxosporidia?

They are obligate parasites with complex spores Signup and view all the answers

What does Nosema apis primarily affect?

Honey bees Signup and view all the answers

What defines microsporidia?

Eukaryotic unicellular organisms that are intracellular parasites Signup and view all the answers

Which organism is known to cause pébrine in silkworms?

Nosema bombycis Signup and view all the answers

What impact does Myxobolus cerebralis have on juvenile salmonids?

Destroys head and vertebral column cartilage Signup and view all the answers

Study Notes

Structure of Protozoa

Pellicle serves as a rigid outer layer in some protozoa, maintaining shape.
Cytoplasm differentiates into ectoplasm (outer) and endoplasm (inner), significant in species with pseudopodia, especially amebas.
Contractile vacuoles assist in osmoregulation, present in protozoa like Naegleria and Balantidium.
Subpellicular microtubules aid slow movement in Apicomplexa, which lack external organelles for locomotion.
Distinctive undulating membranes found in trichomonads and trypanosomes contribute to movement and feeding.
Organelles present include Golgi apparatus, mitochondria, lysosomes, food vacuoles, and conoids in Apicomplexa.

Nutrition

Protozoa are holozoic, requiring organic materials for nutrition, which can be particulate or in solution.
Amebas utilize phagocytosis for food ingestion, digesting in food vacuoles and egesting waste.
Some protozoa possess a permanent cytosome or micropore for feeding.
Pinocytosis involves fluid absorption through temporary openings in the cell membrane that form food vacuoles.
Types of nutrition:
- Autotrophic: Uses light energy for photosynthesis.
- Heterotrophic: Ingests organic material.
- Mixotrophic: Combines autotrophic and heterotrophic methods depending on light availability.

Reproduction

Reproduction can be asexual (binary fission) or sexual.
Binary fission involves organelle duplication and division into two organisms.
Some protozoa, like Testacea, have a protective shell and move via pseudopodia.

Testacea and Foraminifera

Testacea have a siliceous or chitinoid shell, sometimes reinforced with sand grains.
Foraminifera, found in all oceans, have calcium carbonate tests with slender pseudopodia for prey capture and digestion.

Phylum Mastigophora

Zooflagellates are unicellular and may be free-living or parasitic, with one or two flagella for movement and feeding.
Reproduction primarily occurs by binary fission; cyst formation is observed in some species.

Subphyla and Species

Phytomastigina (Class Euglenoidina): Includes Euglena, found in freshwater with flagella and a red eyespot for light orientation. Autotrophic by day, becomes saprozoic in the dark.
Volvocaceae (Class Volvocaceae): Volvox is a colonial freshwater flagellate with cellulose cell walls and flagella.
Opalinea (Class Opalinea): Parasitic, found in amphibian digestive systems; characterized by a large body with cilia.

Phylum Sporozoa

Comprised of endoparasitic protozoans lacking locomotor structures and possessing tough coverings and a single nucleus.
Reproduction includes asexual (multiple fission) and sexual stages involving anisogamy.
Classes:
- Gregarinina: Parasites of invertebrates, low economic significance.
- Coccidiomorpha: Intracellular parasites with significant medical and veterinary importance.

Coccidiida Life Cycle

Eimeria: causes coccidiosis, with symptoms such as severe diarrhea in domestic animals.
Life cycle involves asexual reproduction (schizogony) in host intestinal cells and sexual reproduction (gametogony) leading to oocyst formation.
Infection occurs via sporulated oocysts ingested by new hosts.

Malaria and Piroplasmosis

Malaria, caused by Plasmodium species, leads to significant morbidity and mortality worldwide.
Piroplasmosis affects Equidae, transmitted mainly by ticks, characterized by bloodborne infections.

Phylum Microsporidia

Microsporidia are obligate intracellular parasites that infect a wide range of hosts, including those with strong immune systems.
Notable species include Nosema bombycis (affects silkworms) and Nosema apis (affects honey bees, causing nosemosis).

Conclusion

Protozoa exhibit varied structures, complex nutritional strategies, and multifaceted reproductive strategies, making them significant both ecologically and medically.

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Description

Explore the fascinating structure of protozoa, focusing on the rigid pellicle that helps maintain their shape. This quiz delves into the differentiation of cytoplasm into ectoplasm and endoplasm, along with unique structures like contractile vacuoles and cytosomes. Test your understanding of these microscopic organisms!