The major function of the cell membrane is that it
Answer Details
The major function of the cell membrane is to delimit the cytoplasm, which is the fluid-filled interior of the cell, and to act as a selective barrier that controls the movement of substances into and out of the cell.
The cell membrane is made up of a phospholipid bilayer, which consists of two layers of lipid molecules. This lipid bilayer forms a barrier that separates the inside of the cell from the outside environment. The phospholipid bilayer is also studded with various proteins, which are involved in a variety of functions such as transport, cell signaling, and cell adhesion.
The cell membrane is selectively permeable, which means that it allows some substances to pass through while preventing others from crossing. This selective permeability is important for maintaining the internal environment of the cell and for regulating various cellular processes.
Therefore, the correct option to the question is "delimits the cytoplasm" as it describes the primary function of the cell membrane. The other options listed (synthesizes protein, breaks down worn-out organelles, and is the site for photosynthesis) are functions of other organelles within the cell, such as ribosomes, lysosomes, and chloroplasts, respectively.