Cell Membrane Diagram Labeled, Blank & Printable

Parts of the fluid mosaic model

• Phospholipid bilayer: two layers of phospholipids with hydrophilic heads facing water and hydrophobic tails facing each other.
• Integral (transmembrane) proteins: embedded proteins that may form channels, carriers, or receptors across the membrane.
• Peripheral proteins: loosely attached to one face of the membrane, often for signaling or structure.
• Cholesterol: steroid lipids that help buffer membrane fluidity in animal cells.
• Glycoproteins and glycolipids: lipids or proteins with sugar chains on the extracellular side, forming the glycocalyx for cell recognition.

Cell membrane vs plasma membrane

In most biology courses the terms cell membrane and plasma membrane mean the same structure — the outer bilayer of the cell. “Plasma membrane” emphasizes that it bounds the cytoplasm (protoplasm). Plant cells still have a plasma membrane; the rigid cell wall sits outside it and is a separate structure.

Transport across the membrane

• Simple diffusion: small nonpolar molecules move down their concentration gradient through the bilayer.
• Facilitated diffusion: channel or carrier proteins help polar or charged substances move down their gradient without ATP.
• Active transport: pumps move substances against their gradient using energy (often ATP).
• Osmosis: water moves across the membrane toward higher solute concentration (through the bilayer or aquaporins).

How to use these free diagrams

Post the labeled fluid mosaic diagram while introducing vocabulary, then hand out the blank version of the same layout for students to label from memory. The simple version works for upper elementary or as a warm-up; the transport overview links structure to function. The coloring page is a low-prep station activity. All files are free to view, download, and print with no account required.