The red circle is a lipid. The red circle is a protein. The red circle is a membrane peripheral protein. The red circle is a membrane integral protein. Neither 7 .
Proteins are free to diffuse across the surface of cells.
Lipids can diffuse. The molecule has many hydrophilic groups which would make it impermeable to phospholipid bilayers. This molecule would be transported across a lipid bilayer by a specific protein. Shown below is a membrane protein which you have studied. What is the function of this type of protein.