Final answer:
MERRF is transmitted maternally because traits encoded by mitochondrial DNA are inherited from the mother. Mitochondrial diseases can affect cellular respiration, leading to symptoms like muscle weakness and sensory losses.
Step-by-step explanation:
Myoclonic epilepsy and ragged red fiber disease (MERRF) is a mitochondria-associated disease. Based on cytoplasmic inheritance, MERRF is transmitted maternally. This means that the traits encoded by mitochondrial DNA are inherited from the mother.
Unlike nuclear DNA, which is inherited from both parents, mitochondrial DNA comes exclusively from the ovum. Mitochondrial diseases like MERRF can arise from mutations in the mitochondrial DNA. These mutations can impair cellular respiration, leading to a production of less energy than normal, which in turn may cause symptoms such as muscle weakness, lack of coordination, and loss of vision and hearing.