Mitochondria

Mitochondria39 (MY-toe-CON-dree-uh) (fig. 3.29) are organelles specialized for synthesizing ATP. They have a variety of shapes: spheroid, rod-shaped, bean-shaped, or threadlike. Like the nucleus, a mitochondrion is surrounded by a double unit membrane. The inner membrane usually has folds called cristae40 (CRIS-tee), which project like shelves across the organelle. The space between the cristae, called the matrix, contains ribosomes, enzymes used in ATP synthesis, and a small, circular DNA molecule called mitochondrial DNA (mtDNA). Mitochondria

9mito = thread + chondr = grain 0crista = crest

9mito = thread + chondr = grain 0crista = crest

Spheroid Mitochondria
Outer membrane

Intermembrane space Inner membrane

Intermembrane space Inner membrane

Spheroid Mitochondria

Crista Matrix

Figure 3.29 A Mitochondrion.

Crista Matrix are the "powerhouses" of the cell. Energy is not made here, but it is extracted from organic compounds and transferred to ATP, primarily by enzymes located on the cristae. The role of mitochondria in ATP synthesis is explained in detail in chapter 26, and some evolutionary and clinical aspects of mitochondria are discussed at the end of this chapter (see insight 3.4).

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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