<Tr> <Td> PIKA </Td> <Td> 5 μm </Td> <Td> </Td> </Tr> <Tr> <Td> PML bodies </Td> <Td> 0.2--1.0 μm </Td> <Td> </Td> </Tr> <Tr> <Td> Paraspeckles </Td> <Td> 0.2--1.0 μm </Td> <Td> </Td> </Tr> <Tr> <Td> Speckles </Td> <Td> 20--25 nm </Td> <Td> </Td> </Tr>

What are the various internal cell structures and what do they do