Final answer:
Mitochondria are essential for energy production in cells; dysfunction can lead to diseases with symptoms like fatigue, blurry vision, and muscle spasms. Symptoms vary among individuals due to differences in the distribution of defective mitochondria among cells. Mitochondrial diseases impact cellular energy, affecting various body systems and leading to a range of symptoms.
Step-by-step explanation:
The inability of mitochondria to perform their proper function can lead to a variety of disease symptoms. Mitochondria are essential organelles that produce energy for cells in the form of ATP through aerobic cellular respiration. This energy is crucial for all bodily functions, including muscle contraction and nerve signaling. When mitochondrial diseases occur, they affect the mitochondria's ability to produce this energy efficiently, leading to symptoms such as extreme fatigue, especially after activities like running that require high amounts of energy.
The additional symptoms of blurry vision, muscle spasms, and vomiting can be attributed to energy deficiencies in the muscle cells and cells of the nervous system. For example, cells in the optic nerve require energy to process visual information. When mitochondrial function is compromised, this can lead to visual disturbances. Similarly, muscles need energy to contract and relax properly, and if this energy is not available, it could result in muscle spasms or weakness.
When considering why symptoms appear differently among individuals, such as the differences between Jasmin and her niece, it is important to understand that mitochondrial DNA (mtDNA) mutations may not affect all mitochondria within a cell. As cells divide, daughter cells can end up with a mix of healthy and defective mitochondria, leading to a spectrum of symptoms in individuals with mitochondrial diseases, even within the same family.