Question

Semipermeable cell membranes are made of phospholipids that form a bilayer. What major benefit does this arrangement of the membrane provide to the cell?
a. The cell is able to easily change shape and size
b. Both surfaces of the membrane are nonpermeable
c. The cell has a greater level of structural support
d. Both surfaces of the membrane can interact with water and other molecules.

Answer 1

Answer:

The correct answer would be c. The cell has a greater level of structural support.

Phospholipds are the structural units of a cell membrane. They are consist of two components; hydrphobic lipids and hydrophylic polar heads.

They make a bilayer structure in which polar heads are in contact with water and lipid part are embedded within the layer.

• Lipid bilayer gives the rigidity or shape to the cell.  
• It isolates the cell from the sorroundings.
• It is semi-permiable in nature and thus prevents or control the movement of substances across the membrane.
• Being liquid in nature, the cytoplasm would have dispersed in the surrounding in absence of cell membrane.

Hence, most appropriate choice would be c. The cell has a greater level of structural support.

Answer 2

Answer:

The correct answer is D) Both surfaces of the membrane can interact with water and other molecules.                                                                                                                                                                

Explanation:

Phospholipids provide barriers in cellular membranes to protect the cell, and they make barriers for the organelles within those cells.

Phospholipids work to provide pathways for various substances across membranes. Membrane proteins stud the phospholipid bilayer; these respond to cell signals or act as enzymes or transporting mechanisms for the cell membrane.

The phospholipid bilayer readily allows essential molecules such as water, oxygen and carbon dioxide to cross the membrane, but very large molecules cannot enter the cell in this way or may not be able to at all.

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