Final answer:
The 60S ribosome exit tunnel in eukaryotes is neutral and polar to facilitate the passage of the growing peptide chain without hindrance, with the capacity to accommodate approximately 30-40 amino acids at once.
Step-by-step explanation:
The reason the 60S ribosome exit tunnel is neutral and polar is related to its role in protein synthesis. This environment is crucial for facilitating the movement of the newly synthesized polypeptide chain as it exits the ribosome. The tunnel must accommodate various amino acid side chains; therefore, a neutral and polar environment prevents interactions that could hinder the passage of the growing peptide chain. The exact number of amino acids (AAs) that can fit into the tunnel varies, but it is generally accepted that around 30-40 amino acids can be accommodated within the eukaryotic ribosomal exit tunnel at a given time.