Final answer:
In the nucleus, processes such as nuclear fission, transcription during protein synthesis, and various nuclear reactions affecting protons, neutrons, and energy states occur.
Step-by-step explanation:
Processes that occur in the nucleus include nuclear fission and the production of energy through radioactive processes. In nuclear fission, heavy nuclei, such as those of uranium-235, split into smaller, more stable nucleoids, releasing a large amount of energy in the process. During cell division, transcription - part of protein synthesis - also takes place in the nucleus. This involves using DNA as a template to create RNA, which will then leave the nucleus for translation at a ribosome in the cytoplasm where a protein is synthesized. Moreover, within the nucleus, nuclear reactions can occur that involve changes in the number of protons, neutrons, or the energy state of the nuclei.