Breaks down over time and becomes dirt
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.
In the attachment are some examples:
Answer:
e. All could limit protein mobility
Explanation:
Plasma membrane proteins perform a variety of functions: they act preferentially on transport mechanisms, organizing true tunnels that allow substances to pass into and out of the cell, function as membrane receptors, among other functions. These proteins vary greatly in their mobility, some are as mobile as lipids, while others are practically immobile. But FRAP has revealed that some proteins move in cell membranes much more slowly than in reconstituted liposomes. This limited mobility can be explained by the statement in alternative "E" of the above question.
