nucleic acid genome
Key Terms
nucleic acid genome
capsid
A protein coat that surrounds the nucleic acid core.
envelope
Surrounds the capsid but only some viruses have this not all.
bacteriophages
Viruses that infect bacteria.
phage typing
Identification of bacterial strains using infectivity by different bacteriophages.
virulent phage
A phage that reproduces only by a lytic cycle.
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| Term | Definition |
|---|---|
nucleic acid genome | Passes information from one generation to the next and all viruses have one. |
capsid | A protein coat that surrounds the nucleic acid core. |
envelope | Surrounds the capsid but only some viruses have this not all. |
bacteriophages | Viruses that infect bacteria. |
phage typing | Identification of bacterial strains using infectivity by different bacteriophages. |
virulent phage | A phage that reproduces only by a lytic cycle. |
lyctic cycle | A virulent phage enters the bacterial cell, takes over the activities of the cell for the purpose of making and assembling multiple copies of itself. The host cell bursts open, releasing new viruses. As a result, the bacterial host dies. The entire cycle, from phage attachment to lysis, can take as little as 30 minutes at 37 degrees Celsius to produce 100 to 200 new viruses. |
temperate phage | A phage that is capable of replicating by either a lytic or lysogenic cycle. |
lysogenic cycle | A temperate phage enters the bacterial cell but does not disrupt the functioning of the host cell. The phage nucleic acid becomes integrated into the host DNA and replicates along with it as a prophage. In this way, the host remains alive. However, new phages may be produced when induced into the lytic cycle by an environmental factor. |
prophage | The phage nucleic acid becomes integrated into the host DNA and replicates along with it. |
non-integrative lysogeny | Certain temperate phages may enter the bacterial cell and stay in the cytoplasm as a plasmid. The host activities are not affected and the phage plasmid replicates along with the host cell or independent of its reproduction. Here again, new phages may be produced when the phages switches to lytic cycle. |
plaques | Patches of lysis and area of lysed bacteria representing one initial bacteriophage. |
what was the purpose of the bacteriophage specificity exercise? | To identify potential lysis within a bacterial lawn. |
how do you know if bacteriophage infected the bacteria? | By using the process called phage typing. Plaque formation is usually an indication of bacteriophage that has infected the bacteria. |
why didn't bacteriophage infect all three bacteria? | Because they have to be a match. If they do not match the virus cannot enter the host cell and cannot infect it. |
what is the explanation for bacteriophage specificly when it comes to infecting specific bacterium? | Viruses only infect those cells that have a matching protein to the one that is found on the virus capsid. |
Describe how this exercise demonstrates the principle of phage typing. | It showed what bacteria's were sensitive to lytic T4-Phage suspension. |
List other biological examples in which specific protein interactions are involved? | Pull-down assay, yeast-two hybrid assay. |