Protozoa Overview and Morphology Quiz

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Questions and Answers

What type of cell organization is characteristic of protozoa?

Tissue-level

Unicellular (correct)

Multicellular

Colonial

What is the nutritional type of most protozoa?

Mixotroph

Heterotroph (correct)

Autotroph

Fermenter

Which of the following phyla contains protists of medical interest that are often motile?

Phylum Apicomplexa

Phylum Euglenozoa

Phylum Sarcomastigophora (correct)

Phylum Ciliophora

What aspect of protozoa is NOT primarily associated with their morphology?

Life cycle stages Signup and view all the answers

Which statement about the habitats of protozoa is true?

Protozoa can be found in all moist habitats. Signup and view all the answers

What does the term 'protozoa' mean derived from Greek?

First animal Signup and view all the answers

Which of the following does NOT apply to protozoa?

Only reproduce sexually Signup and view all the answers

Which protozoan characteristic allows them to perform all life functions within a single cell?

Unicellularity Signup and view all the answers

Which part of the protozoan cell is primarily involved in movement and food procurement?

Ectoplasm Signup and view all the answers

What are pseudopodia primarily associated with in protozoan cells?

Movement Signup and view all the answers

What characteristic of ectoplasm is observed under a light microscope?

Transparent and less granular Signup and view all the answers

Which of the following is a function of the ectoplasm in protozoa?

Movement Signup and view all the answers

The nucleus of a protozoan cell is primarily responsible for what?

Cell division and heredity Signup and view all the answers

Which subphylum contains protozoa that use flagella for locomotion?

Mastigophora Signup and view all the answers

What is the primary component of the cytoplasm in protozoan cells?

Ectoplasm and endoplasm Signup and view all the answers

Which of the following describes the endoplasm of a protozoan cell?

Voluminous and complex Signup and view all the answers

What does glycogen vacuole primarily store?

Glucose Signup and view all the answers

How can glycogen vacuoles be visualized in wet mount preparations?

By staining with iodine solution Signup and view all the answers

What are chromatoidal bodies primarily composed of?

Crystalline RNA and RNA-binding proteins Signup and view all the answers

In what type of microscopy can trophozoites of Entamoeba histolytica be observed?

Differential interference contrast microscopy Signup and view all the answers

What type of inclusions may the endoplasm of some protozoa contain?

Bacteria, red blood cells, or other ingested materials Signup and view all the answers

What is the cystic form of apicomplexans referred to as?

Oocyst Signup and view all the answers

What characteristic feature do chromatoidal bodies present under microscopy?

Blunt, rounded ends Signup and view all the answers

Which organism is noted for having ingested erythrocytes in its trophozoite stage?

Entamoeba histolytica Signup and view all the answers

What is the primary method of asexual reproduction in amoebas?

Binary fission Signup and view all the answers

In which of the following organisms does multiple fission occur?

Plasmodium Signup and view all the answers

What are cells called when they undergo schizogony?

Schizonts Signup and view all the answers

What results from the process of cytokinesis during multiple fission?

Production of daughter cells Signup and view all the answers

What term describes the production of more asexually reproducing merozoites in Apicomplexa?

Merogony Signup and view all the answers

In which type of fission does the plane of division remain random?

Binary fission Signup and view all the answers

What happens to the schizont after completing multiple fission?

It ruptures and liberates merozoites. Signup and view all the answers

Which phase follows the release of merozoites during the lifecycle of Apicomplexa?

Merogony Signup and view all the answers

What is the role of trophozoites in the life cycle of protozoa?

They have reproductive powers and are the feeding stage. Signup and view all the answers

Which structure is described as having a 'spokes wheel' arrangement?

Karyosome Signup and view all the answers

What characteristic helps cysts survive in unfavorable environments?

They have a tough cell wall. Signup and view all the answers

In which stage of protozoa does reproductive power primarily occur?

Trophozoite stage Signup and view all the answers

Which characteristic is common to both trophozoites and cysts?

Both have a role in transmission. Signup and view all the answers

What happens to trophozoites when they exist outside the host?

They do not survive long. Signup and view all the answers

What type of protozoa primarily features a compact nucleus?

Ciliates Signup and view all the answers

What is the primary function of chromatin granules in protozoa?

To form an achromatic network. Signup and view all the answers

Study Notes

Protozoa: A General Overview

Protozoa belongs to the Kingdom Protista, are eukaryotic, unicellular, and heterotrophic.
Protozoa perform all life functions within a single cell including reproduction, respiration, excretion, and movement.
Protozoa vary in size and shape, some are visible with the naked eye, others require magnification.
Protozoa are found in all moist habitats including oceans, soil, and fresh water.
Most are non-pathogenic, but some can cause diseases.

Protozoa Morphology

Protozoa are composed of a cytoplasmic body and a nucleus.
Specialized structures within the cell are called organelles which carry out various life functions.
Cytoplasm
- Consists of an outer ectoplasm and inner endoplasm.
- Ectoplasm
  - Is the outer layer, more transparent, less granular, and homogeneous.
  - Contains the plasma membrane which functions in movement, respiration, food intake, waste removal, and protection.
  - The ectoplasm is the origin of locomotion organelles:
    - Pseudopodia: temporary extensions of the ectoplasm found in Amoebas (subphylum Sarcodina).
    - Flagella: long, slender, whip-like structures found in subphylum Mastigophora.
- Endoplasm
  - Is the inner layer, more granular, and contains organelles.
  - May contain:
    - Food vacuoles: for digestion.
    - Inclusions: such as red blood cells, bacteria, or other ingested materials.
    - Glycogen vacuoles: represent the storage form of glucose.
    - Chromatoidal bodies (or bars): dense structures composed of crystalline RNA and RNA-binding proteins.
Nucleus
- May be located centrally or eccentrically.
- Has a karyosome (also known as an endosome) which may be surrounded by chromatin particles arranged in an achromatic network.
- Compact nucleus: found in few protozoa, primarily in ciliates.
  - The chromatin granules are dense, so the nucleoplasm is not visible under light microscopy.
Other Structures:
- Macronucleus (in ciliates): Involved in general cell metabolism and daily activities.
- Micronucleus (in ciliates): Responsible for sexual reproduction.

Protozoa Life Cycles

Protozoa often exist in two developmental stages:
- Trophozoite:
  - The motile, vegetative stage.
  - Replicates and feeds on host cells, responsible for pathogenic effects.
  - Delicate and cannot survive long outside the host.
- Cyst:
  - The resting, non-motile stage.
  - Surrounded by a tough cell wall, making them resistant to unfavorable environments.
  - The infective stage for most protozoa.

Protozoa Reproduction

Protozoa exhibit both asexual and sexual reproduction:
- Asexual reproduction:
  - Binary fission: Protozoa divide into two roughly equal daughter cells. The plane of fission varies by species.
  - Multiple fission: The nucleus and organelles divide repeatedly, followed by cytoplasmic division (cytokinesis) which produces many daughter cells simultaneously.
  - Schizogony: A type of multiple fission in Apicomplexa (e.g. Plasmodium) with daughter cells called merozoites that can initiate further asexual replication (merogony) or sexual reproduction (gametogony).

Summary of Protozoa:

Protozoa are diverse, unicellular eukaryotic organisms mostly found in moist environments.
They have complex cell structures and reproduce through both asexual and sexual processes.
Although most are not harmful, some cause significant diseases.

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Description

Test your knowledge on the general characteristics and morphology of protozoa. This quiz covers essential topics including their life functions, habitats, and cellular structures. Perfect for biology students looking to understand the diversity of this fascinating kingdom.