Final answer:
The length of the average amino acid residue is about 5.4 Angstroms. This length is based on the distance between each turn of the alpha-helix, a common secondary structure in proteins.
Step-by-step explanation:
The length of the average amino acid residue can vary, but on average, it is about 5.4 Angstroms. This length corresponds to the distance between each turn of the alpha-helix, which is a common secondary structure in proteins. However, it's important to note that the length of an amino acid residue can vary depending on the specific protein and its sequence.