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.
The more glycines that are found in a polypeptide's primary sequence, the more flexible the backbone of that polypeptide.
The bridge between cysteines, which connects parts of a protein, is a stable but noncovalent interaction.
Not every amino acid is asymmetric.
At typical cellular pH, the R groups of basic amino acids are positively charged.

Answer 1

The incorrect statement is that the bridge between cysteines in proteins is a noncovalent interaction; it is actually a covalent bond known as a disulfide linkage, crucial for protein tertiary structure stabilization.

Step-by-step explanation:

The incorrect statement among the choices provided for amino acids is that the bridge between cysteines, which connects parts of a protein, is a stable but noncovalent interaction. In truth, the bridge between cysteine residues is formed by a covalent bond known as a disulfide linkage. This link is a result of the oxidation of two cysteine molecules, which combine to form cystine, and it is significant in stabilizing a protein's tertiary structure.

A turn or kink in a protein is indeed more likely to be induced by a proline than by a glycine, due to proline's ring structure. Glycine, having a single hydrogen atom as its side chain, is small and allows flexibility in the protein structure, making the backbone of the polypeptide where glycines are present more flexible. Not every amino acid is asymmetric; for instance, glycine is not chiral. At typical cellular pH, the R groups of basic amino acids such as lysine and arginine are indeed positively charged.

Answer 2

The answer is: The bridge between cysteines, which connects parts of a protein, is a stable but noncovalent interaction.

Step-by-step explanation:

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