The Genetics of Eukaryotic Organisms

The cell cycles of eukaryotic organisms are complex and not only involve changes in morphology but also variation in the genetic complement of the cell. Typically the... 

Two nucleic acids, deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), are found in living things which serve to store, translate, and pass on the genetic information of an organism to the next generation. Nucleic acids are universal to all life, in eukaryotic and prokaryotic cells, as well as in viruses. The mitochondria of eukaryotic cells also contain some DNA, known as mitochondrial DNA. 

The majority of information on the chemical and physical properties of lipids comes from studies on the major phospholipid classes of eubacteria and eukaryotes with only limited information on the lipids from archaebacteria. The biosynthetic pathways and the genetics of lipid metabolism have also been extensively studied in eubacteria (Chapter 3) and eukaryotes (Chapter 8). Clearly, the archaeol lipids confer some advantage with respect to the environment of archaebacteria. Interestingly, the pathways for phospholipid biosynthesis in eubacteria and archaebacteria are very similar even though their lipids differ in chirality of the glycerol backbone. Many of these organisms exist in harsh environments that call for more chemically stable lipid bilayers that are afforded by the above lipids. How the physical properties of the more commonly studied lipids change with environment will be discussed later. 

The cells of humans and other animals are eukaryotes (eu, good karyon, nucleus) because the genetic material is organized into a membrane-enclosed nucleus. In contrast, bacteria are prokaryotes (pro, before karyon, nucleus) they do not contain nuclei or other organelles found in eukaryotic cells. 

In 1966,1 also started a long-term project on the molecular genetics of yeast mitochondria. This model system provided important results as far as both the organization and the evolution of eukaryotic genomes are concerned. These findings will be briefly presented and discussed in Part 2 of this book. In the 1960 s we also performed a series of investigations on the physical chemistry of DNA (see, for instance, Froelich et al., 1963 Freund and Bernardi, 1963) and on transforming DNA from Haemophilus influenzae (Chevallier and Bernardi, 1965, 1968 Bernardi and Bach, 1968 Kopecka et al., 1973). 

What is the purpose of genetic engineering Once the DNA is successfully cloned, it can be expressed using an expression vector and cell line. This allows for the production of eukaryotic proteins quickly and cheaply in bacterial hosts. Genetically altered organisms, such as mice and corn, have been engineered for both pure and applied scientific purposes, and many more changes are to come. 

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