Nuclear pores are actually protein complexes that extend throughout the entire nuclear membrane. And these protein complexes help transport biomolecules such as RNA, ribosomal units, ribosomal proteins, as well as polymerase between our nucleoplasm and our cytosol, the cytoplasm, this region here of our eukaryotic cell. Now, a polymerase is basically a type of enzyme, a type of protein that plays an important role when we translate, replicate or when we transcribe our DNA molecules. And we'll discuss that when we discuss replication, translation as well as transcription. Now, let's move on to a region of the nucleus known as the nucleolus. So at the heart of any nucleus of any eukaryotic cell is a region known as the nucleolus.