The document discusses various methods for predicting protein function, including homology-based transfer of annotation and prediction of functional motifs and domains. Homology-based transfer can infer molecular function from sequence similarity, but biological process is only transferable between orthologs. Orthologs can be detected through phylogenetic trees or automated methods like InParanoid. Each protein domain contributes to molecular function, while short motifs like phosphorylation sites are also important. Functional annotation involves describing proteins at the molecular, biological process, and cellular component levels.