A galaxy where mainly stars and planets form around one or more spiral arms. (usually more?)
It is during G1 phase that a a cell release cdks to initiate the events for cell division. At this stage, b<span>iochemical triggers known as </span>cyclin-dependent kinases<span> (Cdks) switch on cell cycles events at the corrected time and in the correct order to prevent any mistakes.</span>
I'd say, ina general way, that the most imporant cells in defense against parasitic organisms are definitely white blood cels, the cells responsible for defeating antigens, pathogens and deseases.
Although these might be the most important ones in that specific task (defending against parasitic organisms), all the cells in the immune system, along with other non-cell things are important, since they all play a specific role indispensable in our immune system.
Hope it helped,
BioTeacher101
"Viruses straddle the definition of life. They lie somewhere between supra molecular complexes and very simple biological entities. Viruses contain some of the structures and exhibit some of the activities that are common to organic life, but they are missing many of the others. In general, viruses are entirely composed of a single strand of genetic information encased within a protein capsule. Viruses lack most of the internal structure and machinery which characterize 'life', including the biosynthetic machinery that is necessary for reproduction. In order for a virus to replicate it must infect a suitable host cell".
From The Bacteriophage T4 Virus
Answer:
in prokaryotic cells, the control of gene expression is mostly at the transcriptional level. ... Eukaryotic gene expression is regulated during transcription and RNA processing, which take place in the nucleus, and during protein translation, which takes place in the cytoplasm.