Cell Structure And Organelles

Step 1: Understanding Mycoplasmas.
Mycoplasmas are unique among prokaryotes because they lack a cell wall, unlike most other prokaryotes. This gives them flexibility in shape and makes them resistant to antibiotics that target cell wall synthesis.
Step 2: Analyzing the options.
(1) Presence of chitin in cell walls: Incorrect, mycoplasmas do not have chitin in their cell walls.
(2) Presence of murrain in cell walls: Incorrect, mycoplasmas do not have murrain in their cell walls.
(3) Presence of proteins in cell walls: Incorrect, mycoplasmas lack a cell wall entirely.
(4) Absence of cell wall itself: Correct — Mycoplasmas are unique due to the absence of a cell wall.
Step 3: Conclusion.
The correct answer is (4) Absence of cell wall itself.