The term 'ACID TYPE IN PROTEINS' can be solved by the crossword solution 'AMINO'. Amino acids are the building blocks of proteins, and they are essential for life. They are organic molecules that contain an amine group, a carboxylic acid group, and a side chain that is specific to each amino acid. Amino acids are classified as either acidic or basic depending on the pH of their side chain. Acidic amino acids have a side chain with a pH lower than 7, while basic amino acids have a side chain with a pH higher than 7.