Introduction to Protozoa Flashcards
ref: Paniker’s Textbook of Medical Parasitology (8th ed.)
- Single-celled eukaryotic microorganisms
- Found in a wide variety of habitats, including soil, water, and the bodies of animals and plants
- Some protozoa are free-living, while others are parasitic
- Parasitic protozoa can cause a variety of diseases in humans and animals
Protozoa
Features of Protozoa
- a exhibit wide range of size (1-150 µ111)
- Typically have a cell membrane, cytoplasm, and nucleus
- May also have other structures, such as flagella, cilia, or pseudopodia
- Flagella and cilia are used for locomotion
- Pseudopodia are used for movement and feeding
Structure of Protozoa
- trilaminar unit - the outer boundary
- contractile fibrils - responsible for the protozoan’s movement and shape-shifting abilities
What is the function of ectoplasm?
The ectoplasm serves as the organ for locomotion and the engulfment of food by producing pseudopodia. It also helps in respiration, discharging waste material, and providing a protective covering for the cell.
How does ectoplasm facilitate locomotion?
Ectoplasm facilitates locomotion by producing pseudopodia. Pseudopodia are temporary projections of the cell membrane and cytoplasm that extend and contract, allowing the cell to move and change shape.
How does ectoplasm contribute to the engulfment of food?
Ectoplasm plays a role in the engulfment of food by producing pseudopodia. The pseudopodia extend and surround the food particles, forming a temporary food vacuole that will be processed for digestion.
How does ectoplasm help in respiration?
Ectoplasm aids in respiration by facilitating the exchange of gases between the cell and its environment. The thin and flexible nature of the ectoplasm allows for efficient diffusion of gases, such as oxygen and carbon dioxide, across the cell membrane.
What is the role of ectoplasm in discharging waste material?
Ectoplasm is involved in the discharge of waste material from the cell. Waste products are transported to the cell membrane, where the ectoplasm helps in the elimination of these waste materials from the cell.
How does ectoplasm provide a protective covering for the cell?
Ectoplasm forms an outer homogeneous layer that acts as a protective covering for the cell. This layer helps to shield the cell from external factors and provides a barrier against potential damage or invasion.
What are pseudopodia and how are they produced by ectoplasm?
Pseudopodia are temporary protrusions of the cell membrane and cytoplasm that enable cell movement and engulfment of food. Ectoplasm produces pseudopodia by extending and contracting its cytoplasm, allowing the cell to extend and retract these temporary projections.
Can you provide examples of organisms that have ectoplasm?
One example of an organism that has ectoplasm is the amoeba, a single-celled protist. Amoebas use ectoplasmic pseudopodia for locomotion and feeding.
What is the function of endoplasm in the cell?
The endoplasm is the inner granular portion of the cytoplasm that contains the nucleus. It plays a crucial role in various cellular processes, including metabolism, protein synthesis, and the storage of cellular components.
What structures can be found in the endoplasm?
The endoplasm contains several structures, including Golgi bodies, endoplasmic reticulum, food vacuoles, and contractile vacuoles.
How do Golgi bodies contribute to the endoplasm’s function?
Golgi bodies within the endoplasm are involved in the modification, sorting, and packaging of proteins and lipids. They play a crucial role in the secretion of cellular products and the formation of lysosomes.
What is the role of endoplasmic reticulum in the cell?
The endoplasmic reticulum (ER) is a network of membranous tubules and sacs within the endoplasm. It is involved in various functions, including the synthesis and folding of proteins, lipid metabolism, and the detoxification of harmful substances.
How do food vacuoles function within the endoplasm?
Food vacuoles in the endoplasm are responsible for the digestion of engulfed food particles. Once formed, these vacuoles fuse with lysosomes containing digestive enzymes, allowing the breakdown of food and the release of nutrients.
How do contractile vacuoles regulate osmotic pressure?
Contractile vacuoles within the endoplasm help regulate osmotic pressure in the cell. They collect excess water and waste products from the cytoplasm and expel them from the cell, preventing the cell from bursting due to osmotic imbalances.
Can you provide examples of organisms that have contractile vacuoles?
Many freshwater unicellular organisms, such as Paramecium and Amoeba, have contractile vacuoles to regulate water balance and osmotic pressure within their cells.
What is the relationship between ectoplasm and endoplasm within a cell?
Ectoplasm and endoplasm are two distinct regions within the cytoplasm of a cell. The ectoplasm is the outer homogeneous part responsible for locomotion, food engulfment, respiration, waste discharge, and cell protection. The endoplasm, on the other hand, is the inner granular portion that contains the nucleus and houses various cellular structures such as Golgi bodies, endoplasmic reticulum, food vacuoles, and contractile vacuoles.
In a protozoa How many nuclei does the nucleus typically contain?
The nucleus usually contains a single nucleus, but it may also be double or multiple in some species. In certain cases, a single cell can have as many as 100 nuclei.
What is found within the nucleus of a protozoan?
The nucleus contains one or more nucleoli or a central karyosome. These structures are involved in various cellular processes, including the production of ribosomes and the regulation of gene expression.
How is the chromatin distributed within the nucleus?
The chromatin, which contains DNA and associated proteins, can be distributed in two ways. It may be found along the periphery of the nucleus, known as peripheral chromatin, or it can form a condensed mass around the karyosome, a central structure within the nucleus.
What is the function of nucleoli?
Nucleoli are structures within the nucleus that are responsible for the synthesis and assembly of ribosomes, which are crucial for protein synthesis in the cell.
What is the role of the karyosome?
The karyosome is a central structure within the nucleus. Its precise function may vary depending on the organism, but it is involved in processes such as DNA organization and gene regulation.
