Question

Choose the photosynthetic protozoa from the following
a. Euglena
b. Plasmodium
c. Paramecium
d. Amoeba

Answer 1

Hint: Protozoa exhibit various modes of nutrition. Some are parasitic and pathogenic. Others are symbiotic that coexist with other organisms. Many of them feed on other microorganisms and are digested by the larger organisms themselves. A small group have chromatophores and carry out photosynthesis. Most protozoa, however, are heterotopic or holozoic.

Complete answer:
Protozoa are the most primitive group of animal organisms. They are unicellular eukaryotic motile organisms without a cell wall and form a very large and very diverse group that originates from several phylogenetic lineages. Many fossils that are now extinct. Most protozoa are organisms that live freely in aquatic habitats and on the ground.

Mode of Nutrition in Protozoans:
• Holozoic mode of nutrition: Most protozoan take nutrition holozoic ally the protozoan diet consists of microorganisms such as bacteria, diatoms, crustacean larvae, other protozoa, algae, small fragments of large animals and plants, and others. This diet basically includes processes such as food intake, it means Uptake, digestion, ingestion, absorption of undigested residue. It is found in many protozoa such as amoebas and paramecium

• Holophytic mode of nutrition: In this mode, organisms prepare their food from carbon dioxide and water using sunlight using photosynthetic pigments such as chlorophyll. The process is called photosynthesis. Examples are flagellates, Euglenoids, and diatoms.

• Saprophytic nutrition: In this mode, the body releases enzymes into the environment, where the enzymes convert organic matter into simpler products. These products are then absorbed through the body surface. This mode of nutrition is found in slime moulds.

• Parasitic mode of nutrition: Some of the protists get their food from the bodies of other organisms. The individual who receives food is called the parasite, and the organism on which the parasite receives food is called the host. Trypanosomes, Giardia, Entamoeba, Plasmodium are some examples of parasites.

• Symbiotic mode of nutrition: The zoo bulls Trichonympha and Lophomonas live as symbionts in the intestines of termites and wood cockroaches. Both Trichonympha and Lophomonas secrete cellulose digestive enzymes that convert cellulose to glucose. Faulty food (glucose) is shared by the bulls and the zoo host.

• Mixotrophic mode of nutrition: Some protozoa are fed more than one method at the same time or at different times due to changing environments. This is called a mixotrophic diet, i.e. Euglena gracilis and Peranema are both saprozoic and autotrophic in their diet, and some flagellates are autotrophic and zootrophic both.

From the above points it’s clear that Euglena exhibit Holophytic or autotrophic mode of nutrition.
Hence, the correct answer is option (A).

Note: Protozoology is the branch of study of protozoans. Leeuwenhoek first time studied "protozoa", but it's name protozoa was given to him by Goldfus. Protozoa that eat a wide variety of food organisms are called euryphagous, and those that eat only a few types of food are called stenophagous.
Protozoa divided into following groups in the basis of nature of food and mechanism if feeding:
• Macrophages- Macrophages are the protozoans that eat large amounts of food (amoeba).
• Microphagous feeders - Microphages that eat very small particles, rarely stop and their food is taken under running water (Paramecium).
• Fluid conveyors are saprozoic protozoa and parasites that absorb liquid food through their surface (Monocystis).