Question

Indicate true (T) and false (F) statements below regarding peroxisomal proteins. Your answer would be a four-letter string composed of letters T and F only, e.g. TTTF.

( ) All peroxisomal proteins are encoded in the nucleus.
( ) Some peroxisomal proteins are synthesized by ribosomes attached to the rough endoplasmic reticulum.
( ) All peroxisomal proteins reach the organelle after their synthesis is completed.
( ) Peroxisomal proteins have to be unfolded before import.

Answer 1

The statements regarding peroxisomal proteins are TTTF, indicating they are encoded in the nucleus, some are synthesized on the RER, they reach peroxisomes post-translationally, and they do not require unfolding before import.

Step-by-step explanation:

The accurate answers to questions about peroxisomal proteins are:

1. (T) All peroxisomal proteins are encoded in the nucleus.
2. (T) Some peroxisomal proteins are synthesized by ribosomes attached to the rough endoplasmic reticulum (RER).
3. (T) All peroxisomal proteins reach the organelle after their synthesis is completed.
4. (F) Peroxisomal proteins have to be unfolded before import.

Proteins, in general, start their synthesis in the cytoplasm, and peroxisomal proteins are no exception; they also contain oligopeptide signals for their proper targeting and import into peroxisomes. Unlike mitochondrial proteins, peroxisomal proteins do not need to be unfolded prior to import; they can be guided into peroxisomes post-translationally in a folded state.