Biochemistry, 4th Edition P7. Continuing Garrett and Grisham's innovative conceptual and organizing framework, "Essential Questions," BIOCHEMISTRY guides students through course concepts in a way that reveals the beauty and usefulness of biochemistry in the everyday world. Streamlined for increased clarity and readability, this edition also includes new photos and illustrations that show the subject matter consistently throughout the text. New end-of-chapter problems, MCAT practice questions, and the unparalleled text/media integration with the power of CengageNOW round out this exceptional package, giving you the tools you need to both master course concepts and develop critical problem-solving skills you can draw upon. | What Are Viruses 23 TABLE Major Features of a Typical Animal Cell Structure Molecular Composition Function Extracellular matrix Cell membrane plasma membrane The surfaces of animal cells are covered with a flexible and sticky layer of complex carbohydrates proteins and lipids. Roughly 50 50 lipid protein as a 5-nm-thick continuous sheet of lipid bilayer in which a variety of proteins are embedded. Nucleus Endoplasmic reticulum ER and ribosomes Golgi apparatus Mitochondria Lysosomes Peroxisomes Cytoskeleton The nucleus is separated from the cytosol by a double membrane the nuclear envelope. The DNA is complexed with basic proteins histones to form chromatin fibers the material from which chromosomes are made. A distinct RNA-rich region the nucleolus is the site of ribosome assembly. Flattened sacs tubes and sheets of internal membrane extending throughout the cytoplasm of the cell and enclosing a large interconnecting series of volumes called cisternae. The ER membrane is continuous with the outer membrane of the nuclear envelope. Portions of the sheetlike areas of the ER are studded with ribosomes giving rise to rough ER. Eukaryotic ribosomes are larger than prokaryotic ribosomes. The Golgi is an asymmetrical system of flattened membrane-bounded vesicles often stacked into a complex. The face of the complex nearest the ER is the cis face that most distant from the ER is the trans face. Numerous small vesicles found peripheral to the trans face of the Golgi contain secretory material packaged by the Golgi. Mitochondria are organelles surrounded by two membranes that differ markedly in their protein and lipid composition. The inner membrane and its interior volume the matrix contain many important enzymes of energy metabolism. Mitochondria are about the size of bacteria 1 jum. Cells contain hundreds of mitochondria which collectively occupy about one-fifth of the cell volume. Lysosomes are vesicles m in diameter bounded by a single membrane. They .
