Which structural feature distinguishes proline from other natural `alpha-`amino acids?

Which of the following is not an alpha -amino acid?

Which of the following is alpha-"amino" acid ?

Why are amino acids also called alpha - amino acids ?

Which one of the follwing pairs of structures distinguishes a nerve cell from other types of cell

Which one of the follwing pairs of structures distinguishes a nerve cell from other types of cell

Which of the following statements are correct about alpha -amino acids.

Which one is an amino acids?

Write a feature which will distinguish a metallic solid from an ionic solid.

Which is an essential amino acid

Protein are nitrogeneous organic compound having very high molecular mass. They are polyamide formed from alpha -amino acid. The bond formed between two amino acid is called peptide bond (-underset(O)underset(||)C-NH-) . The product obtained by this peptide bond formation are called peptide and they may be divided as di, tri, tetra, penta peptide. Consider following statements concerning protein. 1. All amino acids which are constituents of proteins are alpha -amino acid. 2. alpha -amino acids are all optically active and have L-configuration. 3. An especially favourable conformation for the peptide linkage in protein is the alpha -helix arrangement . 4. alpha -amino acids are connected by ester linkage. Which of the following statement are correct?