The physical distance that separates them on the chromosome.
Answer:
B
Explanation:
The fatty acid tails of phospholipids are hydrophobic – meaning they are ‘water-hating’. This is why they are in the middle of the bi-lipid layer of the cell membrane 'hiding' from the 'watery' environment of a cell. This poses a challenge in the diffusion of large and charged molecules across the membrane -such as sodium ions. Such molecules need transmembrane protein channels to help them cross the membrane. These are called integral proteins because they are part and parcel of the cell membrane. The cell membrane, in addition, also has glycolipids and glycoproteins on its surface that are significant in the identification of the cell by other cells.
