Proteins coded for by nuclear dna but found within mitochondria move from the cytoplasm into mitochondria using

Proteins coded for by nuclear DNA but found within mitochondria move from the cytoplasm into mitochondria using signal sequence.

Protein targeting or sorting is a process by which synthesized proteins are transported to their appropriate localizations in the cell or outside it. Proteins can be targeted to the inner space of an organelle (such as Golgi apparatus, endoplasmic reticulum or mitochondria) or its membrane, plasma membrane, or to exterior of the cell via secretion.  

Usually, protein contains signal sequence on the N terminus that is involved in destination targeting.

organisms that lack symmetry are called asymmetrical and belong to phylum porifera/sponges.

organisms with specialized stinging cells belong to phylum cnidaria. stinging cells are called cnidoblast cells.

cnidarians show two morphological forms : polyp (sessile) and medusa (mobile)

filter feeding is observed in porifera members.  

alternation of generation is observed in coelenterata or cnidaria. there is alternation of asexual polyp form and sexual medusoid form. it is also referred as metagenesis.