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
Insulin is required for glucose transpo in all of the following except: March 2009 
Select and explain. 
A. RBC, B. Skeletal muscles, C. Adipose tissue, D. Hea muscles
A: RBC
Answer: A: RBC 
Explanation: Ans. A: RBCInsulin facilitates entry of glucose into muscle, adipose, and several other tissues.The only mechanism by which cells can take up glucose is by facilitated diffusion through a family of hexose transpoers. In many tissues - muscle being a prime example - the major transpoer used for uptake of glucose (called GLUT4) is made available in the plasma membrane through the action of insulin.