Question

The chemical structure shown below is for sodium lauryl sulfate, a commonly used laboratory detergent. If you added this chemical to a culture of bacteria, they lyse. What would be a reasonable cause for this action on the cells?

Select all that apply:

a. Many SDS molecules in solution will form a micelle due to the hydrophobic tails and the
hydrophilic head.cross out

b. The negatively charged oxygen atom would be exposed on the hydrophilic surface of the membrane.cross out

c. The amphipathic nature of this molecule can result in SDS inserting into the cell membrane.cross out

d. The nonpolar portion of SDS can form van der Waals interactions with the hydrocarbon chains of the phospholipids.

Answer 1

Option C will be the correct.

Detergents like Sodium lauryl sulfate and Sodium decyl sulphate (SDS) have hydrophobic associating properties as a result of their non polar tail groups. These detergents totally disrupt membranes and denature proteins by breaking protein - protein interactions. Generally moderate concentration of detergent compromise the integrity of cell membrane , thereby facilitating the Lysis of bacterial cells.Under certain buffer conditions, these detergents effectively penetrate between the membrane bilayers , at a concentration sufficient to form mixed Micelles with isolated phospholipids and membrane proteins.

Detergent monomers solubilize membrane proteins by partitioning into the membrane bilayer. With increasing concentration of detergent, membranes undergo various stages of solubilization. The first stage is lysis or rupture of the membrane.