Question

If cell wall was used as the only criterion for classifying organisms, then Mycoplasma would have belonged to which one of the following groups?

• A. Animals
• B. Plants
• C. Fungi
• D. Protists

Hint:

Mycoplasmas are the smallest living cells known and lack a cell wall.
Animal cells are the classic eukaryotic cells that lack a cell wall.
No cell wall = Animal-like under this single-criterion system!

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question poses a hypothetical taxonomic scenario: if the presence or absence of a cell wall was the sole criterion used to classify all living organisms, to which major eukaryotic group would Mycoplasma be assigned?

Step 2: Key Formula or Approach:
We need to determine:
1. Whether Mycoplasma has a cell wall.
2. Which of the listed groups (Animals, Plants, Fungi, Protists) are universally characterized by the same cell wall status.

Step 3: Detailed Explanation:

• Mycoplasma are unique prokaryotes belonging to the Kingdom Monera.
- Their most defining morphological feature is the complete absence of a cell wall surrounding their cell membrane. This makes them naturally resistant to antibiotics like penicillin that target cell wall synthesis.

• Now let's look at the cell wall characteristics of the four options:
- Plants: Universally possess a rigid, cellulosic cell wall.
- Fungi: Universally possess a rigid cell wall made of chitin.
- Protists: A highly diverse, heterogeneous group. While some protists (like slime molds and certain algae) possess cell walls, others (like amoebae and paramecia) do not. Thus, they are not a uniform group defined solely by the absence of cell walls.
- Animals: Every single organism in the kingdom Animalia is characterized by the complete lack of a cell wall around their cells.

• Therefore, if having no cell wall was the only criterion, any organism lacking a cell wall—including the bacterium Mycoplasma—would be classified alongside animals.

Step 4: Final Answer:
Due to the complete lack of a cell wall in both Mycoplasma and members of the animal kingdom, Mycoplasma would be grouped with Animals, which is option (A).