Which of the following organisms is an example of a prokaryote?

• A. Paramecium caudatum
• B. Escherichia coli
• C. Saccharomyces cerevisiae
• D. Plasmodium falciparum

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the definition of prokaryotes and eukaryotes. Prokaryotes are organisms whose cells lack a true nucleus and membrane-bound organelles, while eukaryotes have a defined nucleus and organelles.
2. Step 2: Identify the characteristics of each organism listed: Paramecium caudatum is a single-celled eukaryote (a ciliate protozoan), Saccharomyces cerevisiae is a eukaryotic yeast (fungus), Plasmodium falciparum is a eukaryotic protozoan (causes malaria), and Escherichia coli is a bacterium.
3. Step 3: Recall that bacteria are prokaryotes, so among the options, Escherichia coli is the only prokaryotic organism.
4. Step 4: Confirm that the other organisms have membrane-bound nuclei and organelles, which classifies them as eukaryotes.
5. Step 5: Conclude that Escherichia coli is the correct example of a prokaryote in the given list.