Term
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Definition
a preferential outgrowth of selected clones.
-often promoted by acquisition of new genetic information that provides new traits which are beneficial in particular environments |
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Term
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Definition
| alter the genome of a single bacterium |
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Term
| non-random (programmed) mutations |
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Definition
| changes that alter the genome of a single bacterium |
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Term
| direct or indirect transmission |
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Definition
| genetic material between two bacteria that introduces new info into the recipient cell |
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Term
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Definition
1. heritable alterations in the nucleotide sequence of bacterial dna
2. may alter the sequences of the protein or rna encoded by the dna
3. may in rare cases provide the cell a selective advantage
4. arise due to errors made during dna replication (point mutations are most common error) |
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Term
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Definition
| repetition of dna sequence |
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Term
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Definition
| "flip flop" of dna sequence |
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Term
| 4 general mechanisms for exchange of genetic info |
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Definition
1. transformation-uptake of naked dna
2. transduction-transfer involves a bacteriophage
3. conjugation-cell to cell contact required
4. transposition-mobile genetic elements |
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Term
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Definition
1. extrachromosomal elements that are stably inherited
2. exist separately from the bacterial chromosome amd replicate in the cytoplasm
3. replicate autonomously (not linked to chromosomal replication)
4. usually employ the host cell's machinery for replication
5. usually small in size in respect to the bacterial chromosome
6. are commonly circular and composed of dsDNA
7. usually do not encode housekeeping gene required for viability of the host cell thus, plasmids are commonly dispensible to the host cell under most growth conditions
8. some have no identifiable conditions
9. many contain genes which provide a selective advantage to the host cell in certain environments (multiple antibiotic resistance, adhesion, invasiveness, toxins, etc) |
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Term
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Definition
1. genetic elements that have the capacity to mobilize from one site in dna to another site
2. transposition of the elements does not require homologous regions to be shared by the tn and the site of transposition
3. cannot enter a cell without an accesory mechanism ( tn must be delivered to the cell by: a plasmid introduced by transformation or conjugation or an infecting bacteriophage)
4. require a transposase (tnp) which interacts with inverted repeats(ir) located at the termini of the structure
5. insertions of tns can produce gene mutations |
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