Question

Which of the following are true regarding Mycoplasma bacteria? Select all that apply.
a. They have cholesterol in their plasma membranes.
b. They are among the largest bacteria characterized to date.
c. They are pleomorphic.
d. They are also called L-forms.
e. They were initially thought to be viruses.
f. Some can act as pathogens.
g. They are classified in domain Archaea.
h. They are prokaryotes.
i. They are sensitive to penicillin-based drugs.

Accepted Answer

Step 1: Understand the unique characteristics of Mycoplasma bacteria. They are known for lacking a cell wall, which is unusual among bacteria, and this influences their sensitivity to certain antibiotics and their membrane composition. Step 2: Evaluate the statement about cholesterol in their plasma membranes. Unlike most bacteria, Mycoplasma incorporate cholesterol into their membranes, which helps stabilize their membrane structure in the absence of a cell wall. Step 3: Consider their size and shape. Mycoplasma are among the smallest bacteria, not the largest, and they exhibit pleomorphism, meaning they can have variable shapes due to the lack of a rigid cell wall. Step 4: Analyze their classification and historical context. Mycoplasma are prokaryotes, not archaea, and were initially mistaken for viruses because of their small size and filterability. They are not called L-forms; L-forms are cell wall-deficient variants of other bacteria. Step 5: Review their pathogenic potential and antibiotic sensitivity. Some Mycoplasma species are pathogenic to humans, causing respiratory and urogenital infections. Due to the absence of a cell wall, they are resistant to penicillin and other beta-lactam antibiotics that target cell wall synthesis.

Verified video answer for a similar problem:

Key Concepts

Unique Cell Membrane Composition of Mycoplasma

Morphology and Classification of Mycoplasma

Pathogenicity and Antibiotic Sensitivity of Mycoplasma