Final answer:
When a small hole is made in a lipid bilayer, the bilayer will reseal due to the interactions between the hydrophobic lipid tails and hydrophilic heads of the phospholipid molecules. This self-healing property is a consequence of the fluid and dynamic nature of the cell membrane. Significant damage can activate biological membrane repair pathways.
Step-by-step explanation:
If you could poke a small hole in a lipid bilayer, you would expect the bilayer to reseal and close the hole. The lipid molecules in the bilayer have a natural tendency to rearrange themselves to eliminate any gaps due to the hydrophobic properties of the lipid tails and the hydrophilic properties of the heads. These interactions between the phospholipid molecules drive the self-healing property of cellular membranes. If the damage is not too extensive, the bilayer will spontaneously close up, thereby maintaining the essential barrier function of the cell membrane.
When considering the other options, a hole in the bilayer is not likely to remain as a permanent defect because of the dynamic nature of the membrane, and the whole membrane will not unravel and fall apart from a small puncture due to its integrity and resilience. Moreover, in biological systems, certain mechanisms such as membrane repair pathways can be activated to address more significant damage to the membrane.
A reasonable analogy for this self-sealing property is how a water balloon might seal itself after a tiny puncture: the water pressure and the elasticity of the balloon material work together to close the hole.