Final answer:
Proteins destined for the ER and Golgi contain signal sequences recognized by cellular factors that assist in their transport to the appropriate compartments.
Step-by-step explanation:
Proteins destined for the endoplasmic reticulum (ER) and the Golgi contain signal sequences that direct them to the appropriate destinations. These signal sequences are recognized by cellular factors that help transport the proteins to their correct compartments.
For example, a specific sequence at the amino terminus can direct a protein to the mitochondria or chloroplasts in plants. Once the protein reaches its cellular destination, the signal sequence is usually clipped off.