Which statement best describes cell membranes in both plant and animal cells in the context of the lipid bilayer?

• A. They are rigid, nonfluid layers made mostly of cellulose.
• B. They are made primarily of peptidoglycan and lack a lipid bilayer.
• C. They are primarily composed of a phospholipid bilayer with embedded proteins (a fluid mosaic structure).
• D. They are composed mainly of a single layer of triglycerides with no proteins.

Answer: (C)

Verified step by step guidance

1. Understand the basic structure of cell membranes in both plant and animal cells, focusing on the lipid bilayer concept.
2. Recall that the cell membrane is primarily composed of phospholipids arranged in a bilayer, which provides fluidity and flexibility to the membrane.
3. Recognize that proteins are embedded within this phospholipid bilayer, contributing to various functions such as transport, signaling, and structural support.
4. Differentiate the cell membrane from the plant cell wall, which is rigid and made mostly of cellulose, not part of the membrane itself.
5. Conclude that the best description of cell membranes in both plant and animal cells is that they are primarily composed of a phospholipid bilayer with embedded proteins, known as the fluid mosaic model.