遗传学精品教学（南京大学）Chapter 9 Mitochondrial genetics-1.pptVIP

Exp. Anim. 60(5), 421–431, 2011 * * mitochondria are a lovely organelle that once was a bacterium, and during that process the mitochondria transferred their DNA over to the nucleus. That left the mitochondria as basically a double-membraned organelle, with an inner and an outer membrane, and a little bit of remnant DNA that must be inherited when the cells divide. Most proteins, as Harvey has mentioned, are encoded by the nucleus. That means these proteins need to get into the mitochondria. They grow, they make metabolites, they make lipids, and as the mitochondrion gets bigger and bigger, like the bacterium it once was, it also divides. The division is important, because the mitochondria need to go into daughter cells during mitosis, so we also get a complement of mitochondria within each cell that divides. As part of this process of inheritance, mitochondria – as I will show you in a moment – are dynamic structures. They are not just sitting static within the cell; they are players in very important processes. * * We can do that using electron microscopy, but in a somewhat different version. The images here were obtained by using tomography, so you can look at thicker sections and you can look at the tilts, angles, of mitochondria. You get to see inside the mitochondria in more detail, seeing these tubules of what are called cristae formed by the inner membrane, causing invaginations in the mitochondria. So we can look at these and compare them in normal cells and cells that have mitochondria that are defective or have changed. An amoeba (also ameba, am?ba or amoeboid) is a type of cell or organism which has the ability to alter its shape, primarily by extending and retracting pseudopods * adrenal cortex: 肾上腺皮质 * fish pseudobranch： 鱼假鳃； steroid secreting cells:甾族化合物分泌细胞 * Sarcomeres: 肌节 A sarcomere (Greek sarx flesh, meros part) is the basic unit of striated muscle tissue. Skeletal muscles are composed of tubular muscle cells (myocytes called muscle fibers)