1. Nucleus (In Eukaryotes) and nucleoid (In Prokaryotes)
It contains genome (a set of the gene), composed of DNA. DNA is stored and replicated. Nucleus enclosed with the nuclear envelope.
2. Plasma Membrane
It is rigid, flexible, hydrophobic lipid bilayer. The plasma membrane defines the periphery of the cell. It transport proteins, allow passage to specific ions and molecules, receptor proteins transmit signals into the cells and membrane enzymes participate in some reaction pathways. Also, cell growth and cell division occur without loss of membrane integrity.
3. Cytoplasm
The internal volume enclosed by the plasma membrane is known as cytoplasm, composed of an aquous solution the cytosol and a variety of suspended particles with specific functions.
The cytosol is a highly concentrated solution containing enzymes and the RNA molecules.
These RNA molecules encode the amino acids and nucleotide, which assembled hundreds of small organic molecules called metabolites which are intermediates in biosynthetic and degradative pathways. Also contains coenzymes which are essentials for enzyme catalysed reactions, inorganic ions.
Ribosomes are the site for protein synthesis.