This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
[{'content': 'Amphiphatic helices are \nSelect and explain. \nA. α helices having predominantly hydrophobic R-groups projecting from one side and predominantly hydrophilic R-groups projecting from the other side of the axis of the helix, B. Clusters of twisted strands of β sheet, C. Short segments of amino acids that join two units of the secondary structure, D. Supersecondary structures', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Many α helices have predominantly hydrophobic R-groups projecting from one side of the axis of the helix and predominantly hydrophilic R-groups projecting from the other side. These amphipathic helices are well adapted to the formation of interfaces between polar and nonpolar regions such as the hydrophobic interior of a protein and its aqueous environment. Clusters of amphipathic helices can create channels, or pores, through hydrophobic cell membranes that permit specific polar molecules to pass.\nNote: Clusters of twisted strands of β sheet are called β barrels.\nRef: Harper’s illustrated biochemistry. 30th edition page no: 37', 'role': 'assistant'}]