8: Bacterial Genetics Flashcards
(32 cards)
Define auxotroph
A microorganism that requires an organic growth factor. Ex. Amino acid
Define Bacterial Transformation
Mechanism of horizontal gene transfer in which naked DNA is taken up by the recipient cell. (Usually from environment)
Define Conjugation
Mechanism of horizontal gene transfer in which donor cell physically contacts the recipient cell.
Define Genotype
The sequence of nucleotides in an organisms DNA
Define Horizontal Gene Transfer
Transfer of DNA from one organism by a process other than reproduction.
Includes:
Conjugation
Transduction
Bacterial Transformation
Define mutation
A change in the nucleotide sequence of a cell’s DNA that is passed on to daughter cells.
Define Plasmid
A DNA molecule that replicates independently of the chromosome.
Define Prototroph
A microorganism that does not require any organic growth factors.
(Opposite of auxotroph)
Define Transduction
Mechanism of horizontal gene transfer in which bacterial DNA is transferred inside a phage coat.
Define Transposable Element
Segment of DNA that can move from one site to another in a cells genome.
Define vertical gene transfer.
Transfer of DNA from parent to offspring.
Define strain(s).
Genetic variants within a species.
What are the two mechanisms bacteria use to change their genetic code?
Mutation, horizontal gene transfer.
What’s the convention for writing strains of bacteria?
Define spontaneous mutation. What does this mean for a colony?
Random genetic change that results from normal cell processes and are passed to offspring.
This means colonies usually are never exactly identical.
Define reversion.
A mutation that reverts a strain back to its original, non-mutated state.
Define Base-pair substitution. How can this occur?
A type of point mutation that replaces one of the base pairs with another.
This can occur from DNA polymerase incorporating an incorrect base.
Define Synonymous mutation.
Incorporation of the incorrect nucleotide creates a codon that encodes the same amino acid as the original code.
NOT necessarily a silent mutation as the mutation can still cause a change that affects efficiency of translation.
Define missense mutation.
Incorporation of the incorrect nucleotide creates a codon for a different amino acid.
Define nonesense mutation
Incorporation of the incorrect nucleotide creates a stop codon.
Often making protein non-functional.
Define frameshift mutation
Adding or subtracting anything amount of amino acids that isn’t 3. Change the reading frame for mRNA so an entirely different set of codons is translated.
Explain transposition. (Non-homologous recombination)
Integration into new location through a process that does not require a similar nucleotide sequence in the region of recombination.
Simply insertion into a stretch of DNA, does NOT replace the existing sequences.
Define what insertional inactivation is.
The outcome when transportation(non-homologous recombination) occurs and the gene is disrupted by the event, so the gene becomes non-functional.
Define induced mutation.
Genetic changes that occur due to an influence outside of a cell. Ex. Radiation or exposure to chemicals.
