Question

In the plasma membrane, carbohydrates

(a) always faces outwards, towards extracellular space
(b) directed to all sides in the membrane randomly
(c) always faces to the lumen of cells
(d) always faces inward to the nonpolar portion of the membrane

Answer 1

Carbohydrates in the plasma membrane are always located on the exterior surface of cells, bound to proteins or lipids, and play a critical role in cell recognition and interaction.

Step-by-step explanation:

In the plasma membrane, carbohydrates are a major component and are always found on the exterior surface of cells. They are bound either to proteins, forming glycoproteins, or to lipids, forming glycolipids.

Carbohydrate chains range from 2-60 monosaccharide units and may be straight or branched, playing a crucial role in cell recognition by the immune system. This asymmetry is important for the plasma membrane's selective nature, helping cells bind to necessary substances in the extracellular fluid.