BIOS 251 Week 3 Case Study: Cells

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Chamberlain University

BIOS-251 Anatomy & Physiology I

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Date

Brian mentions that a mutation is found in a gene located in the mitochondrial DNA. By highlighting this, Brian is pointing to a unique feature of mitochondrial DNA, distinct from the nuclear DNA, as it is inherited maternally and resides in the mitochondria, the energy-producing centers of cells. The specific mutation is linked to his brother’s condition, Leber Hereditary Optic Neuropathy (LHON), a disease causing vision loss. Since mitochondria generate most of the cell’s energy, a defect in the mitochondrial DNA could impair the energy supply required for proper cell functioning. In the context of the eye, this mutation could result in the cells’ inability to function normally, potentially leading to vision loss.

Mitochondria have a critical role within the cell. According to an article, “Mitochondria are membrane-bound organelles (mitochondrion, singular) that generate most of the chemical energy needed to power the cell’s biochemical reactions” (Gahl, n.d., para. 1). The energy produced by the mitochondria is stored in the form of adenosine triphosphate (ATP), which cells use for energy. Structurally, mitochondria have two membrane layers: an outer membrane and an inner membrane. The outer membrane encloses the organelle, while the inner membrane folds multiple times to form cristae, increasing surface area and giving mitochondria a wrinkled appearance.

BIOS 251 Week 3 Case Study: Cells

This structural difference between mitochondria and a typical eukaryotic cell membrane, which consists of two phospholipid sheets, reflects their distinct roles. The cell membrane, composed of phospholipids, primarily regulates the concentration of substances inside the cell. While the exact mechanism of cell death in the optic nerve caused by mitochondrial defects remains unclear, one hypothesis is that damaged mitochondria might be unable to supply sufficient energy, leading to cellular dysfunction and, consequently, vision loss. Another possibility could be that the condition is inherited.