Chapter II 



Structural and Chemical Architecture of Host Cells with Special 

 Reference to the Synthesis of Polymers 



Seymour S. Cohen 



The Departments of Biochemistry and Pediatrics, University of Pennsylvania 



School of Medicine, Philadelphia, Pennsylvania 



I. Introduction 17 



A. Historical Notes 17 



B. The Metabolic Machinery and Virus Infection 18 



1. The Host as a Source of Metabolites Necessary for Virus Multiplica- 

 tion 18 



2. Viral Enzymes 22 



C. Possible Contributions of the Host Cell to the Synthesis of Viral Poly- 

 mers 25 



D. On the Origin and Cellular Relations of the Viruses 27 



II. Cellular Organization 28 



A. On the Cell in General 28 



B. The Composition of the Nucleus 30 



1. On the Existence of Chromosomes in the Interkinetic Nucleus 39 



2. The Visualization of Intranuclear Constituents 32 



3. The Isolation of Nuclei 36 



4. Some Data on the Composition of Nuclei 38 



5. The Isolation and Composition of Chromosomes 49 



6. Properties of Isolated Mitotic Figures 51 



7. Nuclear Sap 51 



8. Nucleoli 52 



9. Nuclear Membrane 53 



C. Cytoplasmic Structm-es 53 



1. Historical Notes 53 



2. On Cytoplasmic Staining 54 



3. IVIitochondria 55 



4. Biochemical Heterogeneity of Mitochondria 60 



5. Chemical Composition of Mitochondria 61 



6. The Microsomal Fraction 63 



7. Cell Sap or Soluble Supernatant Fraction 66 



8. On the Origin of the Mitochondria and Microsomes 67 



9. Properties of Chloroplasts 67 



III. The Distribution of Metabolic Function 69 



A. Methodological Notes 69 



B. Tables of Enzyme Distribution 71 



C. Enzjrmatic Systems of Nuclei 75 



D. Enzymatic Systems of Cytoplasm 81 



VOL, 1—3 15 



