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
Neutral molecules are transpoed by: 
Select and explain. 
A. Porin channels, B. Ionophores, C. Simple diffusion, D. None of the above
C: Simple diffusion
Answer: C: Simple diffusion 
Explanation: Absence of charge over molecules (Uncharged/Neutral molecules) ours their transpo by simple diffusion. Small neutral molecules are usually transpoed freely across plasma membranes by simple diffusion. Ref: Ganong's Review of Medical Physiology, 22nd Edition, Page 31; Biochemistry By Mary K. Campbell, Shawn O. Farrell, 7th Edition, Page 209; Harper's Textbook of Biochemistry, 27th Edition, Pages 108, 424, 433