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1.5.4: Mitochondria

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    114559
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    A mitochondrion (plural = mitochondria) is an oval membranous structure that generates the majority of ATP within the cell. It consists of an outer and an inner lipid bilayer membrane (Figure 25). The outer membrane serves as a barrier and maintains structural integrity. The space between the outer and inner membranes is where various metabolic processes occur, facilitating communication between the cytoplasm and the mitochondrial matrix. The inner membrane is folded to form structures called cristae, which harbor an array of proteins, enzymes, and molecules that orchestrate the biochemical reactions of cellular respiration, such as the citric acid cycle (Krebs cycle) and oxidative phosphorylation. These reactions convert the potential energy contained in nutrient molecules like glucose into ATP, a form of cellular energy that can be readily utilized. High-energy demand cells, such as muscle cells, necessitate copious amounts of ATP for sustaining muscle contractions. Hence, they house a considerable quantity of mitochondria. Similarly, neurons require substantial ATP to power the activity of their sodium-potassium exchange pumps, prompting their possession of over a thousand mitochondria per cell. In contrast, a bone cell might possess only a few hundred mitochondria, as its metabolic activity is comparably lower 33 , 34 . Mitochondria have their own genetic material.35

    Illustration of a mitochondrion showing the outer membrane, inner membrane, intermembrane space, cristae, and matrix. Labels indicate each part of the organelle structure.
    Figure 25 | The Structure of a Mitochondrion | 36 The figure illustrates the intricate structure of a mitochondrion, the powerhouse of the cell. Mitochondria are double-membraned organelles with distinct compartments that play a crucial role in cellular energy production. The outermost layer acts as a protective barrier, maintaining the structural integrity of the mitochondrion. The space between the outer and inner membranes is where various metabolic processes take place, facilitating communication between the cytoplasm and the mitochondrial matrix. Highly folded to form cristae, the inner membrane houses the electron transport chain and ATP synthase, essential components of oxidative phosphorylation. The central aqueous compartment enclosed by the inner membrane contains enzymes responsible for the citric acid cycle (Krebs cycle) and serves as the site for numerous metabolic reactions.

    This page titled 1.5.4: Mitochondria is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Chaya Gopalan (Consortium of Academic and Research Libraries in Illinois (CARLI)) .