NEETChemistryBiomolecules
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): In proteins, only right-handed helices are observed. Reason (R): Secondary structure of protein refers to the local folding of the polypeptide chain into structures like helices. In the light of the above statements, choose the most appropriate answer from the options given below:
Options
- ABoth (A) and (R) are correct but (R) is not the correct explanation of (A)
- BBoth (A) and (R) are correct and (R) is the correct explanation of (A)
- C(A) is correct but (R) is not correct
- D(A) is not correct but (R) is correct
Correct answer
A. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
Step-by-step solution
According to NCERT, in proteins, only right-handed helices are observed. Thus, the Assertion is correct. The secondary structure of a protein indeed refers to the local folding of the polypeptide chain, with the -helix being a prominent example. Thus, the Reason is also correct. However, the general definition of secondary structure does not explain why only right-handed helices are formed (which is due to the stereochemistry of the constituent amino acids). Therefore, both statements are correct, but the Reason is