《C CHAPTER 4 Eucaryotic Cell Structure and Function nd con Outline Concepts Ine cy 43 70 ed of m ratus 80 4.6 mes 82 d Cell proc 86 ngs 88Prescott−Harley−Klein: Microbiology, Fifth Edition I. Introduction to Microbiology 4. Eucaryotic Cell Structure and Function © The McGraw−Hill Companies, 2002 CHAPTER 4 Eucaryotic Cell Structure and Function Often we exclusively emphasize procaryotes and viruses, but eucaryotic microorganisms also have major impacts on human welfare. For example, the protozoan parasite Trypanosoma brucei gambiense is a cause of African sleeping sickness. The organism invades the nervous system and the victim frequently dies after suffering several years from symptoms such as weakness, headache, apathy, emaciation, sleepiness, and coma. Outline 4.1 An Overview of Eucaryotic Cell Structure 76 4.2 The Cytoplasmic Matrix, Microfilaments, Intermediate Filaments, and Microtubules 76 4.3 The Endoplasmic Reticulum 79 4.4 The Golgi Apparatus 80 4.5 Lysosomes and Endocytosis 80 4.6 Eucaryotic Ribosomes 82 4.7 Mitochondria 83 4.8 Chloroplasts 85 4.9 The Nucleus and Cell Division 86 Nuclear Structure 86 The Nucleolus 87 Mitosis and Meiosis 87 4.10 External Cell Coverings 88 4.11 Cilia and Flagella 89 4.12 Comparison of Procaryotic and Eucaryotic Cells 91 Concepts 1. Eucaryotic cells differ most obviously from procaryotic cells in having a variety of complex membranous organelles in the cytoplasmic matrix and the majority of their genetic material within membrane-delimited nuclei. Each organelle has a distinctive structure directly related to specific functions. 2. A cytoskeleton composed of microtubules, microfilaments, and intermediate filaments helps give eucaryotic cells shape; microtubules and microfilaments are also involved in cell movements and intracellular transport. 3. In eucaryotes, genetic material is distributed between cells by the highly organized, complex processes called mitosis and meiosis. 4. Despite great differences between eucaryotes and procaryotes with respect to such things as morphology, they are similar on the biochemical level