Question

Membrane carbohydrates:

a. comprise about 90% of the molecules in the membrane.
b. can be covalently linked to membrane proteins or to membrane lipids.
c. are found on the inner membrane surface where they interact with cellular organelles.
d. are removed from membranes in the process of glycosylation.
e. are only present in human red blood cells.

Answer 1

Membrane carbohydrates can be linked to membrane proteins or lipids, are found on the cell's exterior surface, and are part of the glycocalyx which aids in cell-water interactions and immune recognition.

Step-by-step explanation:

Membrane carbohydrates can be covalently linked to membrane proteins or to membrane lipids, forming glycoproteins and glycolipids respectively. These carbohydrates are always found on the exterior surface of cells and are crucial for cell recognition, allowing the immune system to differentiate between self and non-self. They make up the highly hydrophilic glycocalyx, which attracts water to the cell's surface and contributes to cell interactions with their watery environment. Contrary to some misconceptions, membrane carbohydrates are neither solely present in human red blood cells nor are they removed via glycosylation; in fact, glycosylation is the process through which these carbohydrates are covalently attached to proteins and lipids in the membrane.