Final answer:
Peroxisomal proteins are synthesized by free ribosomes in the cytoplasm and then directly incorporated into existing peroxisomes via peroxin proteins.
Step-by-step explanation:
Peroxisomes are small, membrane-bound organelles responsible for several important cellular processes, including the breakdown of fatty acids and detoxification of harmful substances. Unlike proteins destined for organelles like the endoplasmic reticulum (ER) or the Golgi apparatus, which are generally synthesized by ribosomes bound to the ER and then transported through the endomembrane system, the proteins for peroxisomes are synthesized by free ribosomes in the cytoplasm. Subsequently, these proteins incorporate into existing peroxisomes using specific targeting signals that are recognized by receptors in the peroxisome membrane. This process is facilitated by peroxin proteins, which play a key role in the formation and maintenance of peroxisomes. When necessary, peroxisomes can grow and divide by a process reminiscent of binary fission to increase their numbers.