A cell can have hundreds of mitochondria.
They are extremely important to the function of the cell producing energy-rich ATP molecules from respiration.
Mitochondria are double membrane organelles.
Like chloroplasts, they contain their own DNA, RNA and ribosomes and are able to make their own proteins independent of the nucleus.
The inner membrane of the mitochondria is called the cristae and the matrix around the cristae is called the stroma.
The enzymes involved in respiration are associated with the cristae membranes.