Question

Which of the following is mixotroph?
A) Plasmodium
B) Amoeba
C) Euglena
D) None of the above

Answer 1

Hint: Mixotrophs are organisms that use different sources of energy and carbon. These organisms exist either as an autotroph or heterotroph. Mixotrophic nutrition is exhibited by Kingdom Protista. More than half of all microscopic plankton are included in mixotrophs. Eukaryotic mixotrophs are of two types-
i) one with their own chloroplast
ii) one with endosymbionts.

Complete answer: Plasmodium is unicellular eukaryotes that are obligate parasites of insects and vertebrates. These organisms are parasites and feed on the blood of the host cell. Thus, they show heterotrophic nutrition.
-These are unicellular, free-living organisms. The mode of nutrition in Amoeba is holozoic nutrition, i.e., phagocytosis. It engulfs the food from its surroundings with the help of finger-like projections, known as pseudopodia.
-These are unicellular, flagellate eukaryotes. They gain nutrition either as autotrophs or as heterotrophs. They act as heterotrophs when sunlight is not available for photosynthesis. Euglenoids like Euglena possess a protein-rich cell membrane which is known as a pellicle. They possess photosynthetic pigments like chlorophyll and thus, are able to produce their own food. They have both plant and animal-like features.
Thus, the correct option is Option C- Euglena.

Note: In organisms with an autotrophic mode of nutrition, they can make their own food with the help of carbon dioxide and water in the presence of sunlight. In organisms with the heterotrophic mode of nutrition, they depend on other organisms for food to survive. Euglena belongs to Kingdom Protista. It acts as both plant and animal.