The antibiotic amphotericin B disrupts plasma membranes by combining with sterols; it will affect all of the following cells except
a. animal cells.
b. gram-negative bacterial cells.
c. fungal cells.
d. Mycoplasma cells.
e. plant cells.

Verified step by step guidance

1. Understand that amphotericin B targets sterols in plasma membranes.
2. Recognize that animal cells, fungal cells, and plant cells contain sterols in their membranes.
3. Recall that Mycoplasma cells, although bacteria, have sterols in their membranes due to their lack of a cell wall.
4. Identify that gram-negative bacterial cells typically do not have sterols in their membranes.
5. Conclude that amphotericin B will not affect gram-negative bacterial cells because they lack sterols.

Key Concepts

Antibiotic Mechanism of Action

Antibiotics like amphotericin B work by targeting specific structures in microbial cells. Amphotericin B disrupts plasma membranes by binding to sterols, particularly ergosterol found in fungal cells. This mechanism leads to increased membrane permeability, causing cell death. Understanding this action is crucial for predicting which types of cells will be affected by the antibiotic.

Cell Membrane Composition

Different types of cells have distinct membrane compositions. Animal cells contain cholesterol, while fungal cells have ergosterol, which is the primary target of amphotericin B. Gram-negative bacteria have an outer membrane that contains lipopolysaccharides, and Mycoplasma cells lack a cell wall, making their membrane composition unique. Recognizing these differences helps determine the susceptibility of various cells to amphotericin B.

Mycoplasma Characteristics

Mycoplasma are a genus of bacteria characterized by their lack of a cell wall, which makes them inherently resistant to many antibiotics that target cell wall synthesis. Their plasma membrane contains sterols, but the absence of a traditional cell wall structure means that amphotericin B's mechanism of action is less effective. Understanding Mycoplasma's unique biology is essential for predicting their response to amphotericin B.