EVERYDAY SCIENCE

Detailed explanation-1: -The experimental evidence that falsified the Davson–Danielli model included membrane freeze-fracturing, which revealed irregular rough surfaces in the membrane, representing trans-membrane integral proteins and fluorescent antibody tagging of membrane proteins, which demonstrated their fluidity within the membrane.

Detailed explanation-2: -The correct answer is #1: integral proteins pass through both membranes. Which of the following statements correctly describe the Davson-Danielli model? #1 It comprises a lipid bilayer coated by a protein layer on the side of the membrane facing inside the cell.

Detailed explanation-3: -The main drawback of a unit membrane model is that it is not sufficient to explain the functioning and structure of complex biological membranes. This model doesn’t account for the numerous proteins that traverse the membrane.

Detailed explanation-4: -As one of the major features of freeze fracture is its ability to provide planar views of membranes, a major emphasis in freeze-fracture cytochemistry is to identify integral membrane proteins, study their spatial organization in the membrane plane, and examine their role in dynamic cellular processes.