Question

Do mitochondria have DNA?

Answer 1

Hint: Mitochondria is a membrane bound organelle which is found in most of the multicellular eukaryotes and also in some unicellular organisms and is popularly known as the powerhouse of the cell.

Complete answer:
The size of the mitochondria ranges from 0.75 to 3 square micrometers. The shape of the mitochondria may be various but the structure is the same in all organisms. It consists of an outer membrane, an intermembrane space, an inner membrane, cristae and matrix. The outer membrane is made up of proteins and phospholipids and plays an important role in protein translocation.

The intermembrane space is freely permeable to small molecules and allows their passage from the outer to the inner membrane. The inner membrane performs the most important function of ATP synthesis by carrying out the electron transport chain and also helps in passage of metabolites to the mitochondrial matrix. The cristae comprises finger-like projections and enhances the mitochondria’s ability in ATP synthesis.

The matrix consists of ribosomes, tRNA and mitochondrial DNA which is different from the DNA present in the nucleus of the cell. The mitochondrial DNA encodes its own proteins that are required for ATP synthesis and other mitochondrial processes and this DNA is transferred only from the mother to the offspring by a process known as maternal inheritance.


Note: The mitochondrial DNA is important in proper functioning of the mitochondria, mutations in the DNA cause serious illness such as exercise intolerance, Kearns- Sayre syndrome and also ageing related processes and age associated pathologies.