Final Answer:
True. Not all integral membrane proteins contain transmembrane alpha helices.
Step-by-step explanation:
While transmembrane alpha helices are a common structural feature in integral membrane proteins, not all of them possess this characteristic. Integral membrane proteins are embedded within the lipid bilayer of biological membranes, and their structures can vary. Some integral membrane proteins have transmembrane alpha helices that span the lipid bilayer, providing stability and anchoring the protein in the membrane. However, other integral membrane proteins may utilize different structural motifs, such as beta-barrels or lipid anchors, to interact with the membrane without necessarily forming transmembrane helices.
Therefore, the statement is accurate; not all integral membrane proteins contain transmembrane alpha helices.
Option A) True is the answer.