Which of the following statements best describes what happens to a cell exposed to polymyxins that destroy phospholipids?
a. In an isotonic solution, nothing will happen.
b. In a hypotonic solution, the cell will lyse.
c. Water will move into the cell.
d. Intracellular contents will leak from the cell.
e. Any of the above might happen.

Verified step by step guidance

1. Understand the role of polymyxins: Polymyxins are antibiotics that target and disrupt the phospholipid bilayer of bacterial cell membranes.
2. Consider the effect of phospholipid destruction: When phospholipids are destroyed, the integrity of the cell membrane is compromised, leading to increased permeability.
3. Analyze the consequences of increased permeability: With a compromised membrane, intracellular contents can leak out, and the cell can no longer regulate the movement of substances in and out effectively.
4. Evaluate the scenarios: In an isotonic solution, the balance of solutes inside and outside the cell means no net movement of water, but the cell is still vulnerable to leakage. In a hypotonic solution, water will move into the cell, potentially causing it to lyse due to osmotic pressure.
5. Conclude the most likely outcome: Given the destruction of the membrane, intracellular contents leaking from the cell is a direct consequence of the action of polymyxins.

Key Concepts

Polymyxins and Cell Membrane Disruption

Polymyxins are a class of antibiotics that target the bacterial cell membrane by disrupting phospholipid structures. This disruption compromises the integrity of the membrane, leading to increased permeability. When the membrane is damaged, it can no longer effectively regulate the movement of substances in and out of the cell.

Isotonic vs. Hypotonic Solutions

An isotonic solution has the same solute concentration as the cell's interior, resulting in no net movement of water. In contrast, a hypotonic solution has a lower solute concentration outside the cell, causing water to move into the cell. This influx can lead to swelling and potential lysis if the cell membrane is compromised.

Cell Lysis and Leakage of Intracellular Contents

Cell lysis occurs when the cell membrane is unable to withstand the osmotic pressure, leading to rupture. When polymyxins disrupt the membrane, intracellular contents, such as enzymes and nucleic acids, can leak out. This leakage can severely affect cellular function and viability, ultimately leading to cell death.