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: Physiology
The transmembrane region of the protein is likely to have- 
Select and explain. 
A. A stretch of hydrophilic amino acids, B. A stretch of hydrophobic amino acids, C. A disulphide loop, D. Alternating hydrophilic and hydrophobic amino acids
B: A stretch of hydrophobic amino acids
Answer: B: A stretch of hydrophobic amino acids 
Explanation: The transmembrane proteins lie similar to that of the lipid bilayer. The lipid bilayer is hydrophilic in the outer and the inner parts and has a hydrophobic core. 
Similarly, the transmembrane proteins have outer and inner ends which are hydrophilic and a core which is hydrophobic. 
So the transmembrane region of the protein is hydrophobic.