Biology · Cell Structure and Function

Option C is correct since integral proteins are embedded in the 'phospholipid bilayer' of the membrane, the mobility of the integral proteins is determined largely by the physical state of membrane phospholipids.

Amino acids are the building blocks of proteins, including integral membrane proteins. While the properties of the amino acids can influence the structure and function of the integral proteins, they do not directly affect the physical state of the membrane or the mobility of the proteins within the membrane.

External phospholipids, such as those found in the extracellular fluid or in the outer leaflet of the cell membrane, can interact with the membrane proteins and affect their function, but they do not directly affect the physical state of the membrane or the mobility of the integral proteins within the membrane.

The mobility of integral proteins in the cell membrane can be measured by the physical state of the membrane phospholipids. The physical state of the membrane phospholipids can affect the mobility of the integral membrane proteins.

Membrane appendages, such as microvilli or cilia, are extensions of the cell membrane that have specialized functions, but they do not directly affect the physical state of the membrane or the mobility of the integral proteins within the membrane.