Question

Which of the following organisms is NOT an example of eukaryote?
(a) Amoeba proteus
(b) Paramecium caudatum
(c) Escherichia coli
(d) Euglena viridis

Answer 1

Hint: E.coli is a unicellular prokaryote belonging to kingdom monera. Other species such as Amoeba proteus, Paramecium caudatum and Euglena viridis are unicellular eukaryotes. They belong to Kingdom Protista. Thus, E.coli is an example of prokaryote and not eukaryotic.

Complete answer:E.coli is unicellular organisms, with a primitive nucleoid, containing a naked circular DNA with extrachromosomal gene, the plasmid. The ribosomes of E.coli is of the 70s type.
Thus, E.coli belongs to prokaryotes. On the other hand, eukaryotes either unicellular or multicellular are surrounded by a true nucleus with a linear double stranded DNA. The ribosomes of eukaryotes are of 80s type.
Thus, E.coli, unicellular bacteria possessing all characteristic features similar to prokaryotic belonging to prokaryotes and kingdom monera. Rest of the organisms which possess characteristic features similar to unicellular eukaryotes belong to the kingdom protista.

Note:Amoeba proteus is nonparasitic protozoan
Paramoecium caudatum have two types of nuclei (nuclear dimorphism),smaller micronucleus or reproductive nucleus and larger macronucleus/vegetative nucleus
Euglena possesses the character of both plants and animals so it is a connecting link between plants & animals. Euglena viridis shows mixotrophic nutrition