Ribosomes: These complex proteins, along with other cell mechanisms, are responsible for converting the DNA you put inside the cell into proteins. They essentially act to translate DNA into a product that does something (along with RNA polymerases)
Chromosome DNA: This is a gigantic circular chromosome, there are around 4 million base pairs worth of genetic information. Usually, all of the essential proteins such as energy production enzymes, structural proteins etc. are encoded here. It is the 'Essential DNA' of the cell.
Plasmid DNA: These are smaller circular pieces that are around 4,000 base pairs in size. They encode 'accessory' proteins that may give the cell new functions, but aren't essential for the cell to live. Scientists insert their own modified plasmids to give the cells new functions, this is how you will change the cell's function as well.
Cell wall: This wall surrounds the cell and protects it from bursting open in water, toxic chemicals etc.