Which description correctly explains how signal peptides direct proteins to mitochondria, chloroplasts, and secretory pathways?

• A. ER signal sequences direct nascent proteins to mitochondria.
• B. Mitochondria and chloroplasts use identical targeting signals as the secretory pathway.
• C. Signal peptides direct nascent proteins to specific destinations; ER signals direct secretory and membrane proteins; mitochondria and chloroplasts have targeting peptides recognized by translocases enabling import to these organelles.
• D. Secretory pathway proteins lack targeting signals.

Answer: (C)