This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Proteins bonds and structure, Subject name: Biochemistry
The peptide bond has all the following characteristics, EXCEPT:- 
Select and explain. 
A. Covalent in nature, B. Planar in nature, C. Paial double bond character, D. Free to rotate
D: Free to rotate
Answer: D: Free to rotate 
Explanation: A peptide bond is a special type of amide bond -Characteristics of peptide bond:- Planar Uncharged Takes pa in hydrogen bonding Trans in configuration Rigid, because of paial double bond character - no rotation is possible