Question

all cells contain cell membranes. which of the following describes the composition of cell membranes?
a. cell membranes are composed of carbohydrate chains, which allow all materials to enter and leave the cell.
b. cell membranes are composed of cellulose, which provide rigidity for the cell.
c. cell membranes are composed of cytoplasm, which allows proteins to be excreted by the cell.
d. cell membranes are composed of lipid molecules, which provide a flexible structure.

Explanation:

La membrana celular está compuesta por una bicapa lipídica, que es flexible y permite la entrada y salida selectiva de moléculas. Las cadenas de carbohidratos no son la composición principal (A está mal). La celulosa es parte de la pared celular (no de la membrana, B está mal). El citoplasma no forma la membrana (C está mal). La lipídica (lípidos) sí forma la membrana y es flexible (D está bien).

Answer:

D. Cell membranes are composed of lipid molecules, which provide a flexible structure.