Biological membranes are present in all cells, and in eukaryotic cells they also form the endomembrane system. They act as gatekeepers that selectively move certain ions and compounds into and out of the cell or cell organelles. Which statement best describes a biological membrane? a bilayer containing lipids with hydrophilic head groups facing inward and hydrophobic tail groups extending toward the extracellular fluid and cytoplasm a bilayer containing lipids with hydrophobic head groups facing the extracellular fluid and cytoplasm, and hydrophilic tail groups extending inward a bilayer containing lipids with hydrophilic head groups facing the extracellular fluid and cytoplasm, and hydrophobic tail groups extending inward Which biomolecules are components of biological membranes? nucleic acids proteins lipids How is the biological membrane bilayer held together? crosslinks noncovalent interactions peptide bonds covalent bonds

A bilayer containing lipids with hydrophilic head groups facing the extracellular fluid and cytoplasm, and hydrophobic tail groups extending inward.

Proteins and Lipids

The biological membrane bilayer is held together by non covalent interactions.

Explanation:

The structure of the biological membrane is such that the major components found in this membranes are phospholipids although other components are present including various proteins, glycolipids etc. These phospholipids forms a bilayer (two layer) and each phospholipid has an hydrophilic head group (which is attracted to the fluidic environment both extracellular and cytosolic environment) and a hydrophobic tail (which is insolube in both environment). the arrangement is such that the hydrophilic heads of both bilayer that love water faces these two envirionments while the hydrophobic tails of both layers extend towards each other.

The biological membrane bilayer is held together by non covalent bonds. the proteins and lipid molecules in the bilayer are held together by this non covalent bonds including van der waals forces which also holds the hydrophobic tails together. the hydrogen bonds bind the hydrophilic heads with water allowing for the stabilization of the structure.

answer: the correct option is d. enzyme

lactase and carbonic anhydrase are the examples of enzymes.

lactase is an enzyme, which is present in the small intestine of mammals. it in the digestion of the disaccharide, lactose ( milk sugar) by converting it into two monosachharide, which are glucose and galactose.

carbonic anhydrase is present in the red blood cells. this enzyme plays significant role in the transport of co₂. it in the conversion of co₂ and h₂o into carbonic acid, which is then dissociated into bicarbonate ions and hydrogen ions.