Question

Most bacteria live in a hypotonic solution. The hypotonic solution has a higher percentage of water when compared to the interior of a bacterium. Given the environment that the cell exists in, the function of the cross-linked peptidoglycan cell wall of the bacteria is to:

a) Prevent the cell from bursting due to osmotic pressure.
b) Facilitate the uptake of nutrients.
c) Provide structural support.
d) Regulate the cell's internal pH.

Answer 1

The primary role of the bacterial cell wall, made of peptidoglycan, is to prevent cell rupture in hypotonic environments. Compounds that inhibit cell wall synthesis leave bacteria vulnerable to osmotic lysis, which is a basis for the action of certain antibiotics.

Step-by-step explanation:

Most bacteria are found in hypotonic environments where the concentration of solutes outside the cell is lower than inside, leading to a net influx of water into the cell. The role of the cross-linked peptidoglycan cell wall is primarily to prevent the cell from bursting due to the osmotic pressure that results from this imbalance.

If a compound that interferes with the synthesis of the cell wall is added to this environment, the protective layer that normally provides structural support and withstands the osmotic pressure will be compromised. Without an intact cell wall, bacterial cells are much more susceptible to bursting, or osmotic lysis, because they lack the necessary rigidity to resist the pressure caused by the water entering the cell. This is why antibiotics that inhibit cell wall synthesis, such as penicillin, are effective at killing bacteria.