Question

which side is the extracellular side of the cell membrane illustrated below? how do you know?

the top is the extracellular side because membrane diagrams are usually drawn in the same orientation with the outside of the cell on the top.

you cannot determine which is the extracellular side without more information.

the top is the extracellular side because it has glycans attached, which act as signals and cellular \street addresses\.

the bottom is the extracellular side because the top has sugar molecules attached, and the concentration of sugars is higher inside the cell than out.

the bottom is the extracellular side because there are peripheral membrane proteins attached to the top, and these must function in signaling within the cell.

Explanation:

Glycans (sugar - containing molecules) are typically found on the extracellular side of the cell membrane. They play important roles in cell - cell recognition, signaling, and act as "cellular street addresses". Just because a diagram is drawn in a certain orientation (like top being outside) is not a reliable scientific reason. Also, the concentration of sugars is not higher inside the cell compared to the outside in the context of glycan - containing molecules on the membrane. Peripheral membrane proteins can be on either side depending on their function, but the presence of glycans is a more definitive indicator.

Answer:

The top is the extracellular side because it has glycans attached, which act as signals and cellular "street addresses".