Biological membranes are present in all cells, and they make up the endomembrane system of eukaryotic cells. Among other functions, they act as barriers that selectively allow the transport of small molecules and ions into and out of the cell or organelle.
Which of the following best describes a biological membrane?
a. a bilayer containing lipids with hydrophilic head groups pointing inward and hydrophobic tail groups oriented toward the solvent (extracellular fluid and cytosol)
b. a bilayer containing lipids with hydrophilic head groups oriented toward the solvent (extracellular fluid and cytosol) and hydrophobic tail groups pointing inward
c. a bilayer containing lipids with hydrophobic head groups oriented toward the solvent (extracellular fluid and cytosol) and hydrophilic tail groups pointing inward
Which of the following are components of biological membranes? Select all that apply.
a. proteins
b. nucleic acid
c. proteins

-A bilayer containing lipids with hydrophilic head groups oriented toward the solvent (extracellular fluid and cytosol) and hydrophobic tail groups pointing inward.

-Option (a) and (c).

Explanation:

The cell membrane is highly selective and semi permeable membrane that allows the movement of some selected particles only. The cell membrane protects the cell from the outside and inside environment of the cell.

The cell membrane is composed of the lipids and proteins. The bliayer of the lipid consists of hydrophilic head and hydrophobic tails. The hydrophilic head lies outside or in the extracellular side and whereas the hydrophobic tail is present inside the membrane. The peripheral protein, transmembrane protein and integral membrane protein are the important proteins of the biological membrane.

Thus, the correct answer is -option (b).

- option (a) and (c).