![](/olcweb/styles/shared/spacer.gif) | ![](/sites/dl/free/0072320427/title/cover_image.JPG) Foundations in Microbiology, 4/e Kathleen Park Talaro,
Pasadena City College Arthur Talaro
Microbial Genetics
Chapter Overview- Genetics is the study of the structure and function of the genomes of biological entities.
- The primary levels of heredity lie in the chromosomes, genes, and the DNA molecule.
- DNA is a very elongate molecule composed of deoxyribose, phosphate, and nitrogenous bases arranged in a double helix.
- The two DNA strands are held together by pair bonding between matched sets of purine and pyrimidine bases: adenine pairs with thymine; cytosine pairs with guanine.
- The arrangement of the base pairs along the length of DNA provides detailed instructions for the formation of proteins, key components of cell structure and metabolism.
- The DNA molecule must be replicated for the distribution of genetic material to offspring.
- Interpretation of the DNA is accomplished by transcription of its code into helper molecules of RNA that cooperate to translate the code into proteins.
- During protein synthesis on the ribosomes, codons of mRNA are sequentially matched by a complementary anticodon on tRNA, which ensures the correct amino acid is added to the protein.
- Viruses contain various forms of DNA and RNA that are translated by the genetic machinery of their host cells to form functioning viral particles.
- The genetic activities of cells are highly regulated by operons, groups of genes that interact as a unit to control the use or synthesis of metabolic substances.
- DNA undergoes mutations, permanent changes in its language, that alter the expression of genes and serve as a force in evolution of organisms.
- Bacteria undergo genetic recombination through transfer of genes in the form of small pieces of DNA, transposons, or circular plasmids.
- Forms of recombination in bacteria include conjugation, transformation, and transduction.
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