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most of genetic information in a bacterium located
within single chromosome
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plasmids
- -number of closed loops of DNA
- -Exist as independent units apart from bacterial chromosome; contain 2% of total genetic info, multiply independently of chromosome
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mutation
permanent change in organism's DNA
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Causes of Mutation
- as a result of identifiable factors known as mutagens,
- -UV radiation - known mutagen
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transposons
- small segments of DNA that have ability to move from one position to antoher in bacterial chromsome
- -segments carry no genetic information other than for ability to insert to chromosome
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gene recombination
transfer of drug resistance taken place
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three methods of gene recombination
conjugation, transduction, and transformation
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conjugation
two live bacterial cells come together, donor cell transfer some genetic material to recipient cell
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F factor
- a plasmid of the donor cell, meaning 'fertility factor'
- -contains 20 genes, assocated with conjugation, genes encode enzymes that replicate DNA and move from donor to recipient
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F pili aka sex pili
special pili, hairlike fibers that contact recipient bacteria, then retract so surfaces of donor and recipient so close that a bridge forms
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transduction.
gene transfer occurs with assistance of a bacterial virus
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bacterial viruses that are in transduction are known as ..
bacteriophages
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transformation
- bacterium acquires genes from its surrounding environment
- -occurs very limited percentage of bacteria in a population
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competence factors
protein molecules that believe to allow DNA fragments to pass thru bacterial cell membrane
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endonucleases
bacterial enzymes, aka restriction enzymes, cuz help bacteria "restrict" bacteriophage replication by destroying page's nucleic acid within bacterial cytoplasm
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