Question

What evidence convinced Overton that membranes were composed of lipids?

1) He could see the lipids in the microscope.
2) Membranes were destroyed by enzymes that degraded lipids.
3) He found that more lipid-soluble solutes enter root hair cells faster than polar solutes.
4) Membranes dissolved in gasoline.
5) Membranes did not dissolve in water.

Answer 1

The evidence that convinced Overton of the lipid composition of cell membranes was the faster entry of lipid-soluble substances into cells compared to polar solutes, supporting the idea that membranes are amphipathic with selective permeability.

Step-by-step explanation:

What evidence convinced Overton that membranes were composed of lipids? Overton was convinced of the lipid nature of cell membranes because he found that lipid-soluble substances entered root hair cells faster than polar solutes.

This observation aligns with the understanding that cell membranes are amphipathic, containing hydrophobic and hydrophilic regions, allowing them to create a barrier in the aqueous environment of the cell. As a result, membranes permit the passage of nonpolar, lipid-soluble molecules more readily than polar molecules, which struggle to penetrate the hydrophobic lipid core of the membrane. This core concept is critical to the fluid mosaic model of the cell membrane, which posits that the membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids.