Genetics+of+Viruses+and+Bacteria

=__Genetics of Viruses and Bacteria__= By: Jacee Stoner

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 * Chapter 18 notes

Vocabulary
Bacteriophage/ Phages: Bacterial Virus Capsid: Protein shell that encloses the viral genome Host Range: The range of what a virus can infect or parasitize Lyctic Cycle : defined below Lysogenic Cycle: defined below Retrovirus: RNA viruses with the most complicated reproductive cycles Transformation: defined below Transduction: defined below Conjunction: defined below Transposon: defined below Insertion Sequence Operons


 * Chapter 18**

Parts of a phage

Head: is surrounded by caspid which contains the viral genome Capsid: Defined above Tail Sheath (Baseplate): Used to attach to a bacterium Tail fibers: Used to attach to a bacterium

__Viral Reproduction Pg.323__ Viruses can only reproduce within a host cell and each virus can only infect a limited range of host cells, also known as host range.

The Lytic Cycle This results in the death of the host cell. In the last stage of infection the host cell is filled with many phages and then it breaks open and releases the phages that were produced within the cell. Each phage can then infect another healthy cell and repeat the process. The Lysogenic Cycle This does not result in death of the host cell. The DNA molecule is incorporated by crossing over into the host cells chromosome. It then basically remains silent within the bacterium and each time the host cells prepares to replicate, the phage DNA replicates along with it. Retroviruses have an enzyme called reverse transcriptase which uses RNA as a template to create DNA.

__Genetics of Bacteria__- How new bacterial strands are produced Transformation: The alteration of the bacterial cells genotype by the uptake of naked foreign DNA from the surrounding environment. When a nonpathogenic cell uptakes pathogenic DNA which then goes through genetic recombination (exchange of DNA through crossing over) Transduction: Phages carry bacterial genes from one host cell to another. There are two forms of transduction: Generalized and specialized. Conjugation: A direct transfer of genetic material between two bacterial cells that are temporarily joined. Transposons: (Transposable genetic element) A piece of DNA that can move from one location to another in a cells genome.

__Websites__ A good site for information on [|Viral Infections].