Answer:
Step-by-step explanation:
When Brian mentions that the mutation is in a gene found in the mitochondrial DNA, he is referring to a specific type of DNA that is located within the mitochondria of cells. Mitochondrial DNA is separate from the nuclear DNA found in the cell's nucleus. It is inherited maternally and contains genetic information necessary for the functioning of mitochondria.
The main function of mitochondria within cells is to generate energy in the form of ATP (adenosine triphosphate) through a process called cellular respiration. Mitochondria are often referred to as the "powerhouses" of the cell because they produce the majority of ATP needed for various cellular activities, including metabolic processes and maintaining cell viability.
The composition of the mitochondrial membrane differs from that of a eukaryotic cell membrane. The mitochondrial membrane consists of two layers: the outer mitochondrial membrane and the inner mitochondrial membrane. The outer membrane is permeable to many small molecules, while the inner membrane is highly selective and contains various transport proteins and enzymes involved in ATP synthesis. The inner membrane is also folded into structures called cristae, which increase the surface area available for ATP production. Additionally, the mitochondrial membrane contains specific proteins and enzymes necessary for various metabolic reactions within the mitochondria.
In comparison, the composition of a eukaryotic cell membrane, such as the plasma membrane, includes a phospholipid bilayer with embedded proteins and cholesterol. It serves as a selectively permeable barrier, regulating the movement of substances in and out of the cell. The cell membrane also plays a role in cell signaling, cell adhesion, and maintaining cellular homeostasis.
Regarding the hypothesis on how defects in the mitochondria can cause cell death in the optic nerve, one possible explanation relates to the high energy demands of optic nerve cells. Optic nerve cells require a significant amount of ATP to function properly and transmit signals from the eye to the brain. If there are defects in mitochondrial function, ATP production may be impaired, leading to insufficient energy supply for the optic nerve cells. This energy deficiency can disrupt cellular processes, compromise cell viability, and eventually result in cell death in the optic nerve.