Optic Neuropathy (LHON) that results from a mutation in the mitochondrial DNA
Sample Solution
Mitochondrial DNA (mtDNA) is the genetic material found in the mitochondria, which are organelles within the cell that generate energy. MtDNA is separate from the nuclear DNA, which is the genetic material found in the nucleus of the cell.Full Answer Section
Brian mentioned mtDNA because LHON is a disease that is caused by mutations in mtDNA genes. These mutations can disrupt the function of the mitochondria, which can lead to cell death.
2. What is the main function of the mitochondria within the cells?
The main function of the mitochondria within the cells is to generate energy. Mitochondria do this by converting glucose and oxygen into ATP, which is the energy currency of the cell. ATP is used to power all cellular processes, including muscle contraction, protein synthesis, and active transport.
3. Describe the composition of the mitochondrial membrane and compare that with the composition of a eukaryotic cell membrane. What are the functions of cell membranes?
The mitochondrial membrane is composed of a phospholipid bilayer, similar to the eukaryotic cell membrane. However, the mitochondrial membrane also contains a number of proteins that are involved in energy production and other mitochondrial functions.
The eukaryotic cell membrane is also composed of a phospholipid bilayer, but it contains a different set of proteins than the mitochondrial membrane. The eukaryotic cell membrane is responsible for regulating the movement of substances into and out of the cell.
The functions of cell membranes include:
- Protecting the inside of the cell from the external environment
- Regulating the movement of substances into and out of the cell
- Providing a surface for cell-cell communication
- Maintaining the structure of the cell
4. Although it is unclear how defects in the mitochondria can cause cell death in the optic nerve, what would be your hypothesis on how this can happen knowing the function of the mitochondria within the cell?
My hypothesis is that defects in the mitochondria can cause cell death in the optic nerve by disrupting the energy supply to the cells. The optic nerve is a highly specialized tissue that requires a lot of energy to function properly. If the mitochondria are not functioning properly, they may not be able to produce enough energy to meet the needs of the cells. This can lead to cell death and vision loss.
Another possibility is that defects in the mitochondria can lead to the production of reactive oxygen species (ROS). ROS are harmful molecules that can damage cells. If the optic nerve cells are exposed to too many ROS, they may die.
It is also possible that defects in the mitochondria can lead to the release of pro-apoptotic proteins. Pro-apoptotic proteins are proteins that trigger cell death. If too many pro-apoptotic proteins are released, the optic nerve cells may die.
More research is needed to fully understand how defects in the mitochondria cause cell death in the optic nerve. However, the hypotheses above provide some possible explanations.
Scholarly Resource
- Berninger, B., Reyes, A., & Gorman, G. S. (2012). Leber hereditary optic neuropathy: Mitochondrial dysfunction and cell death. Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease, 1822(12), 1931-1939.
This article provides a comprehensive overview of LHON, including the role of mitochondrial dysfunction in the disease.