Question

Which of the following statements about amino acids is incorrect?A turn or kink in a protein is more likely to be induced by a proline than by a glycine.At typical cellular pH, the R groups of basic amino acids are positively charged.The bridge between cysteines, which connects parts of a protein, is a stable but non-covalent interaction.Not every amino acid is asymmetric.The more glycines that are found in a polypeptide's primary sequence, the more flexible the backbone of that polypeptide.

Answer 1

The incorrect statement about amino acids is that the bridge between cysteines, which connects parts of a protein, is a non-covalent interaction. In reality, the bridge is a disulfide linkage, which is a type of covalent bond.

Step-by-step explanation:

Among the statements provided about amino acids, the incorrect one is: "The bridge between cysteines, which connects parts of a protein, is a stable but non-covalent interaction." This statement is false because the interaction between cysteine side chains forms disulfide linkages, which are indeed covalent bonds and provide significant stabilization to the protein's tertiary structure.

A turn or kink in a protein can indeed be induced by a proline residue due to its unique ring-like structure and its impact on the protein's backbone flexibility. Glycine, having the simplest side chain of a hydrogen atom, contributes to the flexibility of the protein backbone. At typical cellular pH, basic amino acids, such as lysine and arginine, have positively charged R-groups. Additionally, not all amino acids are asymmetric since glycine is an exception due to its two hydrogen atoms attached to the alpha carbon, making it achiral.

Answer 2

The correct answer is The bridge between cystein which connects parts of a protein is stable but non covalent interaction.

Step-by-step explanation:

Disulfide bond link the sulfhydryl group of two adjacent cystein residues in a protein structure.

Dulsulfine bond is stable but is not a non covalent interaction.Disulfide bond itself is a covalent interaction.