Dear Student
Yes, Mitochondria is present in almost all eukaryotic organisms. A notable exception includes the mature Erythrocytes or Red Blood Cells which lack mitochondria.
Mitochondrion is a membrane-enclosed organelle found in eukaryotic cells.
Mitochondria are responsible for the production of most of the energy (or ATP) in cells. Therefore, mitochondria are also known as the power house of cells. A mitochondrion is composed of two lipid membranes, enclosing the matrix. The inner membrane gets folded to form numerous cristae. Cristae are the main site for ATP production. Mitochondrial matrix contains mitochondrial DNA and ribosomes
Functions of mitochondria:
They produce energy required for cells in the form of ATP.
They also regulate the free calcium ion concentration in the cytosol.
They participate in apoptosis or programmed cell death.
Regards