Ciliophora: Characteristics and Functions

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Questions and Answers

What is the primary role of cilia in ciliates?

For reproduction only

For motion and modified feeding (correct)

To produce energy through photosynthesis

To store genetic material

What is a distinguishing feature of the macronucleus in ciliates?

It contains haploid chromosomes

It undergoes genetic recombination

It is derived from the micronucleus and contains multiple genome copies (correct)

It divides by meiosis

What occurs during the process of conjugation in Paramecium?

Only the macronucleus is replicated

An exchange of haploid nuclei occurs via a cytoplasmic bridge (correct)

Cells exchange DNA without fusing nuclei

Two cells undergo binary fission simultaneously

What is the function of the cytoproct in ciliates?

For waste removal through exocytosis Signup and view all the answers

How do ciliates primarily reproduce when not undergoing sexual reproduction?

By transverse fission Signup and view all the answers

What happens to the macronucleus during conjugation in Paramecium?

It disintegrates after the exchange of nuclei Signup and view all the answers

In ciliates, food vacuoles are formed for what main purpose?

To ingest food and regulate water balance Signup and view all the answers

Which of the following processes must progeny from sexual division complete before they can conjugate?

Complete 50 asexual divisions Signup and view all the answers

What happens to Paramecium after approximately 600 asexual reproductions?

It dies due to loss of mate recognition. Signup and view all the answers

Which of the following statements about Apicomplexa is true?

They form spores that can infect hosts. Signup and view all the answers

Which organism is a key member of the Apicomplexa group?

Plasmodium Signup and view all the answers

What is the role of the Anopheles mosquito in the life cycle of Plasmodium?

It transmits sporozoites to humans. Signup and view all the answers

What occurs in the body of the Plasmodium after a person is infected by a mosquito?

The liver cells are invaded and merozoites are formed. Signup and view all the answers

What factors contribute to the complexity of Plasmodium's life cycle?

Both sexual and asexual reproduction occur. Signup and view all the answers

Which of the following is NOT a symptom of malaria?

Headaches Signup and view all the answers

What challenge has emerged in efforts to control malaria transmission?

Development of resistant strains of parasites and vectors. Signup and view all the answers

How do sponges differ from other multicellular organisms?

They do not possess tissues and organs. Signup and view all the answers

Which cells in sponges are responsible for aiding the feeding process?

Choanocytes (collar cells) Signup and view all the answers

Study Notes

Ciliophora (Ciliates)

Heterotrophic unicellular protists with a diverse range of sizes.
Characterized by numerous cilia arranged longitudinally or in spirals; cilia are anchored to microtubules under the cell membrane.
Coordinated beating of cilia enables movement and modified cilia serve as mouthparts for feeding.
Flexible outer covering, known as pellicle, provides structural support.
Possess two types of nuclei: micronuclei (diploid, involved in meiosis and genetic recombination) and macronuclei (derived from micronuclei, involved in routine cell functions like protein synthesis).

Feeding Mechanism

Food enters through the gullet, which is lined with cilia, directing it to food vacuoles.
Digestive enzymes and hydrochloric acid in food vacuoles break down food.
Nutrients are absorbed; waste is expelled through cytoproct, an exocytotic vesicle that periodically removes waste.

Reproductive Strategies

Reproduce through transverse fission, creating two identical daughter cells (Protor and Opisthe), with both micronuclei and macronuclei dividing.
Paramecium can undergo up to 700 generations of asexual reproduction before degeneration without sexual reproduction.
Sexual reproduction (conjugation) involves two genetically distinct individuals exchanging genetic material through a cytoplasmic bridge.
Meiosis produces haploid micronuclei, which fuse with existing micronuclei to form new diploid micronuclei.
Post-conjugation, macronuclei disintegrate; one micronucleus remains while another evolves into a macronucleus after replication.
Progeny from sexual division need around 50 asexual divisions to undergo conjugation; after approximately 600 divisions, mate recognition diminishes.

Apicomplexa (Sporozoans)

Non-motile spore-forming parasites infecting animals, characterized by a unique arrangement of organelles.
Important members include Plasmodium species responsible for malaria: P.falciparum, P.malariae, P.ovale, and P.vivax.
Complex life cycles with both sexual and asexual reproduction; sexual reproduction initiates when the large female gamete is fertilized by a smaller male gamete.
Oocysts form and undergo meiotic division, producing haploid spores (sporozoites) which infect hosts.

Malaria Transmission

Plasmodium spreads via Anopheles mosquitoes, which inject sporozoites into the bloodstream during feeding.
After reaching the liver, sporozoites reproduce asexually, forming merozoites that invade red blood cells, leading to their rupture.
This cycle results in symptoms such as fever and chills, recurring every 48 or 72 hours.

Control & Immunity

Resistance to insecticides like DDT has developed, complicating vector elimination.
Strains of Plasmodium have also shown drug resistance, increasing infection rates.
Vaccination efforts are progressing, focusing on antigens produced at different life cycle stages.
Symptoms of malaria include fever, chills, and splenomegaly; severe complications can lead to death.
Malaria control measures involve vector elimination, drug development, and vaccine research.

Porifera (Sponges)

Complex multicellular organisms lacking true tissues, organs, and symmetry; exist in marine and freshwater environments.
Body structure consists of loosely coordinated cells; adults are sessile while larvae are mobile.
Specialized choanocytes (collar cells) line body cavities and chambers, facilitating feeding and water flow.
Gelatinous layer called mesohyl acts as an endoskeleton, providing structural support for the sponge’s tubular shape.

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Description

Explore the fascinating world of Ciliophora, unicellular protists distinguished by their cilia and complex structure. This quiz covers their feeding mechanisms, reproductive strategies, and unique nuclei types, highlighting their adaptability in various environments.