Final answer:
The presence of a transit sequence in a protein leads it from the cytosol to the mitochondrion or chloroplast, involving specific signal peptides that direct the proteins after post-translational modification.
Step-by-step explanation:
The presence of a transit sequence directs a protein from the cytosol to the mitochondrion or chloroplast. This is a process where proteins synthesized in the cytosol, which are destined for these organelles, contain specific oligopeptide traffic signals. These traffic signals direct proteins to their appropriate destinations after post-translational modification. Mitochondrial protein transfer, for example, involves a folded protein exposing an N-terminal signal peptide that binds to a receptor protein at the outer mitochondrial membrane, facilitating its import into the organelle.