What causes increased permeability in membranes at higher temperatures?

Increased permeability of membranes at higher temperatures is primarily linked to the denaturation of membrane proteins. As temperature rises, the kinetic energy of molecules increases, which can disrupt the interactions that maintain the structure and integrity of membrane proteins. These proteins play crucial roles in regulating what enters and exits the cell, and any alteration in their structure can lead to increased fluidity within the membrane.

As proteins denature, their functional shape changes, which can compromise the selective barrier provided by the membrane. This alteration allows a greater flow of substances, contributing to increased permeability. This is especially important in biological systems where temperature regulation is crucial for maintaining homeostasis.

The other choices do not directly explain the phenomenon of increased permeability due to temperature changes. For instance, increased pigment concentration does not inherently affect membrane structure or permeability, nor does the formation of new membranes necessarily imply increased permeability. Additionally, bond formation generally decreases with heat due to higher energy states leading to movement rather than stability. Thus, the denaturation of membrane proteins is the key factor driving increased permeability in this context.