As temperature increases, membrane fluidity

As temperature increases, membrane fluidity

• A. Decreases
• B. Stays the same
• C. Fluctuates
• D. Increases

Answer: (D)

Membrane fluidity rises with temperature because heat increases the kinetic energy of the lipid molecules in the bilayer. As temperature goes up, the phospholipid tails wiggle more and pack less tightly, breaking up orderly arrangements and allowing the molecules to diffuse laterally more easily. This greater molecular motion matches the fluid nature described by the membrane model, so the membrane becomes more fluid as heat increases. The other ideas—that fluidity would decrease with heat, stay unchanged, or simply fluctuate—don’t fit the straightforward relationship between heat and molecular movement in the bilayer.

Membrane fluidity rises with temperature because heat increases the kinetic energy of the lipid molecules in the bilayer. As temperature goes up, the phospholipid tails wiggle more and pack less tightly, breaking up orderly arrangements and allowing the molecules to diffuse laterally more easily. This greater molecular motion matches the fluid nature described by the membrane model, so the membrane becomes more fluid as heat increases. The other ideas—that fluidity would decrease with heat, stay unchanged, or simply fluctuate—don’t fit the straightforward relationship between heat and molecular movement in the bilayer.