Which of the following organism is an example parasitic nutrition?

Question

Prepp Team · Accepted Answer

Understanding Parasitic Nutrition in Organisms

Parasitic nutrition is a mode of nutrition where an organism, known as the parasite, lives on or inside another living organism, the host. The parasite obtains its food and shelter from the host, often causing harm to the host in the process. Parasites are dependent on their hosts for survival.

Analyzing Organisms and Their Nutritional Modes

Let's examine the nutritional modes of the organisms listed in the options:

Algae: Algae are typically photosynthetic organisms. They contain chlorophyll and produce their own food using sunlight, water, and carbon dioxide. This mode of nutrition is called autotrophic nutrition. Therefore, algae are not examples of parasitic nutrition.
Selaginella: Selaginella is a genus of lycophytes, which are vascular plants. Like most plants, Selaginella is photosynthetic and obtains energy through autotrophic nutrition. It produces its own food and does not depend on another organism for nourishment in a parasitic way.
Amoeba: Amoeba is a single-celled organism that obtains food through holozoic nutrition. It engulfs food particles from its environment, digesting them internally. While it is heterotrophic (obtaining food from external sources), its method is typically predation or scavenging, not parasitism on a specific host organism in the way viruses are parasitic.
Virus: Viruses are acellular entities, but they exhibit a form of life when inside a host cell. They are obligate intracellular parasites. This means they cannot replicate or carry out metabolic processes on their own. They inject their genetic material into a host cell and use the host's machinery (ribosomes, enzymes, energy) to produce new virus particles. This process often damages or kills the host cell, fitting the definition of parasitic nutrition where the parasite lives within and relies on the host, causing harm.

Why Virus is an Example of Parasitic Nutrition

Based on the analysis, the Virus is the organism among the options that demonstrates parasitic nutrition. Viruses invade living cells of other organisms (plants, animals, bacteria, etc.) and live inside them, hijacking the host's cellular processes for their own reproduction. They derive all the resources needed for replication from the host cell, thus acting as parasites.

Organism	Nutritional Mode	Is it Parasitic Nutrition?
Algae	Autotrophic (Photosynthesis)	No
Selaginella	Autotrophic (Photosynthesis)	No
Amoeba	Holozoic (Heterotrophic)	No (typically not parasitic in the given context)
Virus	Obligate Intracellular Parasitism	Yes

Revision Table: Key Nutritional Modes

Mode	Description	Example Organisms
Autotrophic	Organisms produce their own food, usually through photosynthesis or chemosynthesis.	Plants, Algae, some Bacteria
Heterotrophic	Organisms obtain food by consuming other organisms. Includes:	Animals, Fungi, some Bacteria, Protozoa
	Holozoic: Ingestion, digestion, absorption, assimilation, egestion.	Amoeba, Humans, Animals
	Saprophytic: Obtain nutrients from dead organic matter.	Fungi, some Bacteria
	Parasitic: Obtain nutrients from a living host, causing harm.	Viruses, some Bacteria, Fungi, Plants (e.g., Cuscuta), Animals (e.g., Tapeworm)

Additional Information on Parasitic Organisms

Parasitism is a common ecological relationship. Parasites can be classified in various ways:

Ectoparasites: Live on the surface of the host (e.g., ticks, lice).
Endoparasites: Live inside the host's body (e.g., tapeworms, malaria-causing Plasmodium, Viruses).
Facultative Parasites: Can be parasitic but do not require a host to complete their life cycle.
Obligate Parasites: Cannot complete their life cycle without a host (Viruses are obligate parasites).

Parasitic relationships highlight the complex interactions between different organisms in an ecosystem.