Question

Which one of the following organisms is not an example of eukaryotic cells?
A. Amoeba proteus
B. Paramecium caudatum
C. Escherichia coli
D. Euglena viridis

Answer 1

Hint: Eukaryotic cells are cells that contain a nucleus and organelles, and are enclosed by a plasma membrane. Organisms that have eukaryotic cells include protozoa, fungi, plants, and animals.

Complete answer:
-Amoeba proteus: Amoebae are eukaryotes whose bodies most often consist of a single cell. This means that they have membrane-bound organelles, including a membrane-bound nucleus.
Its ability to change shape is from pseudopodia, which are common in eukaryotic microbes.
-Paramecium caudatum: Paramecia are eukaryotes. Paramecium caudatum is a species of unicellular protist in the phylum Ciliophora. The species is very common and widespread in marine, brackish and freshwater environments.
-Escherichia coli: Escherichia coli, also known as E. coli, is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacteria of the genus Escherichia that is commonly found in the lower intestine of warm-blooded organisms. E. coli is a unicellular bacterium (single-cell organism) and it comes under the category of Prokaryotes. "Pro-karyotic" is Greek word which means “before nucleus”. They are prokaryotes as they do not contain any organized nucleus with a distinct membrane and nor other specialized organelles.
-Euglena viridis: Euglena is unicellular, eukaryotic microorganisms. This means that the euglena is made up of one complex cell, containing many organelles. Euglena viridis is a common, solitary and free-living freshwater flagellate.
So, the answer is C, i.e., Escherichia coli

Note: Prokaryotes have a prokaryotic cytoskeleton that is more primitive than that of eukaryotes. Besides homologs of actin and tubulin, the helically arranged building-block of the flagellum, flagellin, is one of the most significant cytoskeletal proteins of bacteria, as it provides structural backgrounds of chemotaxis, the basic cell physiological response of bacteria.