Term
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Definition
| The uptake of DNA from the medium (from lysed cells), and incorporation into the host chromosome. |
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Term
| What is the effect of DN'ase on the process of transformation? |
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Definition
| Will degrade the DNA before uptake can occur. |
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Term
| Is transformation common among Gram -, +, or both? |
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Definition
| It is observed in many Gram positives and Gram negatives. |
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Term
| Which type of bacteria secrete competence factors? |
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Definition
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Term
| What occurs in Gram +'s upon the binding of competence factors? |
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Definition
| The synthesis of 8-12 new proteins, including autolysin. |
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Term
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Definition
| Exposes a DNA-binding protein and nuclease on cell surface by degrading peptidoglycan. |
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Term
| How selective is the DNA-binding protein on the surface of Gram +'s? |
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Definition
| Not selective at all. It will uptake any dsDNA including human! |
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Term
| What occurs once the dsDNA binds the DNA-binding protein on the surface of the Gram + bacteria? |
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Definition
| One strand is hydrolyzed as the other strand associates with proteins and crosses the CM. |
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Term
| In what form does DNA enter Gram - bacteria during transformation? |
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Definition
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Term
| What allows Gram - bacteria to be selective in their transformation? |
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Definition
DNA must contain a specific 11bp sequence for binding
5’AAGTGCGGTCA
5’GCCGTCTCAA for N. gonorrhoeae |
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Term
| Cells capable of undergoing transformation are called? |
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Definition
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Term
| A method for making E. Coli cells competent is. |
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Definition
| treatment with cold CaCl2. |
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Term
| Is it easier to transform plasmids, linear DNA, or are both the same? |
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Definition
| Transformation of plasmids is easier than linear pieces of DNA. |
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Term
| In order to perform electroporation cells must be made electrocompetent. How is this done? |
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Definition
| Washing in cold distilled water. |
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Term
| Describe the method/process of electroporation. |
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Definition
| Electrocompetent cells are mixed with DNA and exposed to high voltage pulses in an electroporator. Small resealable holes are made in the membrane which allows DNA in. |
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Term
| Transduction is described as: |
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Definition
| Genetic exchange between two bacteria mediated by a phage. |
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Term
| Describe the process of transduction. |
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Definition
| During a phage infection bacterial genes are packaged by error into a phage head. The phage then injects this DNA into another bacterium. |
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Term
| What is the difference between virulent bacteriophages, and temperate bacteriophages? |
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Definition
| Virulent bacteriophages reproduce using the lytic life cycle, and temperate bacteriophages reproduce using the lysogenic life cycle. |
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Term
| Which phage life cycle always results in lysis of the bacterial cell? |
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Definition
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Term
| Describe the five steps in the lytic lifecycle. |
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Definition
1. adsorption (specific receptors)
2. injection of DNA (capsid stays outside)
3. phage DNA directs synthesis of phage DNA and phage proteins
4. packaging of DNA into heads
5. lysis of bacterium and release of new progeny
phage |
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Term
| What typically causes the excision of prophage DNA during the lysogenic cycle? |
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Definition
| Exposure to stress such as UV light. |
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Term
| What is a transducing particle? |
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Definition
| A phage containing bacterial DNA. |
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Term
| Why will generalized transduction never result in the production of new phages? |
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Definition
| The transducing particle never gives rise to new phages because it has no phage DNA. |
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Term
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Definition
| A lysogen is a phage that can exist as a DNA in its dormant state (prophage) within its host organism. |
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Term
| Where does lambda phage DNA always integrate? |
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Definition
| Between the gal and bio genes. |
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Term
| What is the medical importance of lysogenic infection? |
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Definition
| The rash in scarlet fever, and diphtheria toxin. |
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Term
| What makes specialized transduction so special? |
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Definition
| Due to an error in excision of the prophage only the genes next to the integration of phage DNA (gal and bio in the case of lambda) are taken up. Specialized transducing particles have both phage and bacterial DNA, therefor infection can give rise to new phage. |
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Term
| How do these match up to Gray's? |
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Definition
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