The name of the part of the cell shown in the diagram depends on the specific part visible in the image, but common key parts labeled in cell diagrams include the nucleus, cytoplasm, cell membrane, mitochondria, Golgi apparatus, endoplasmic reticulum, and lysosomes. If the diagram shows the center of the cell containing chromosomes and DNA, it is most likely the nucleus. The nucleus is often the most conspicuous organelle in a eukaryotic cell and is responsible for storing the cell's genetic material and coordinating activities like DNA replication and RNA synthesis. If you can provide a description or more detail of the diagram, I can specify the exact name of the part shown.