One component is the nucleus. This organelle contains the genetic information of the cell, in the form of DNA.
Another component is the mitochondira. This is the site of respiration in the cell and therefore the production of energy.
Ribosomes are the site of protein synthesis within the cell.
The cytoplasm is the site of chemical reactions within the cell; it is also responsible for the exchange of nutrients between the inside and outside of the cell.
The cell membrane acts to keep the internal and externals environments of the cell separate, by allowing the selective exchange of nutrients.