Cytoplasm
In cell biology, the cytoplasm is all of the material within a cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. The main components of the cytoplasm are cytosol – a gel-like substance, the organelles – the cell's internal sub-structures, and various cytoplasmic inclusions. The cytoplasm is about 80% water and usually colorless.
Nuclear pore
As the NPC controls access to the genome, it is essential that it exists in large amounts in stages of the cell cycle where plenty of transcription is necessary. For example, cycling mammalian and yeast cells double the amount of NPC in the nucleus between the G1 and G2 phase of the cell cycle, and oocytes accumulate large numbers of NPCs to prepare for the rapid mitosis that exists in the early stages of development. Interphase cells must also keep up a level of NPC generation to keep the levels of NPC in the cell constant as some may get damaged. Some cells can even increase the NPC numbers due to increased transcriptional demand.