Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
41 Cards in this Set
- Front
- Back
|
Selective mutations
|
Confer an advantage on the cell under certain environmental conditions; ex antibiotic resistance. Here the progeny can outgrow and replace the parent
|
|
|
Unselective Mutations
|
Athought they can have phenotypic effect, they do not confer an advantage; ie loss of pigmentation.
|
|
|
What type of approach does it take to detect unselectable mutant
|
screening approach
|
|
|
What is replicate plating and example of?
|
Sceening approach
|
|
|
Novel negative selection that is widely used to isolate auxotrophic mutants.
|
Penicillin Selection (or enrichment)
|
|
|
Genetic selection
|
Used for antiobiotic resistant. Resistant cells appear in zone of inhibition.
|
|
|
Auxotrophs
|
Cells that do not grow on minimal medium, but grow on complete medium.
|
|
|
Spontaneous Mutations
|
Are the result of the action of natural radiation and errors in replication.
|
|
|
Point Mutations
|
Most mutations are these, these can be basepair substitutions, insertions or deletions of a single base pair.
|
|
|
A faulty protein would arise from this mutation.
|
Missense mutation
|
|
|
An incomplete protein would arise from this mutation.
|
Nonsense mutation
|
|
|
A normal protein would arise from this type of mutation.
|
Silent mutation
|
|
|
Frameshift
|
Deletion or insertion of base pairs that disrupts the reading frame of a gene.
|
|
|
Conditional Mutants
|
Base pair changes when the phenotype of the mutant is observed only under specific growth conditions.
|
|
|
Temperature sensitive
|
Mutants exhibit a wild type phenotype at low (permissive) temperature and a mutant phenotype at high (nonpermissive) temperatures.
|
|
|
This type of mutation is reversible.
|
Point mutation
|
|
|
Same site revertant (true revertant)
|
the change in the base pair is converted back to its original sequence
|
|
|
Second site revertant
|
A mutation occurs at a site other than the original mutation that restores the phenotype.
|
|
|
Intragenic
|
When a suppressor mutation occurs on the same gene.
|
|
|
Mutations in a gene encoding a tRNA is an example of what?
|
Nonsense suppression
|
|
|
These increase the rate of mutagenesis.
|
Chemical mutagens and DNA repair mutations.
|
|
|
Occurance of a nonsense mutation is
|
10e-6 -- 10e-8
|
|
|
Alkylating agents
|
put methyl on G; faulty pairing with T
|
|
|
Ethidium Bromine
|
Insert between two base pairs
|
|
|
What is the wavelength for UV light
|
260nm
|
|
|
UV light
|
Pyrimidine dimer formation
|
|
|
Ionizing radiation (X rays)
|
Free radical attack on DNA, breaking chain
|
|
|
What is the result of UV or ionizing radiation?
|
repair may lead to error or deletion
|
|
|
Ethidium bromide results in?
|
Microinsertions and microdeletions
|
|
|
Alkyating agents result in?
|
GC-->AT
|
|
|
Bromouracil
|
Incorporated like T; occasionally faulty pairing with G
|
|
|
What is the result of adding BU?
|
AT pair-->GC pair occasionally GC--> AT
|
|
|
What is an assay fir reversion of an auxotrophic his mutant?
|
Ames Test
|
|
|
Transposable elements
|
mobile DNA elements that can "jump" into new sites of the genome.
|
|
|
Conservative insertion
|
The original element moves from one position to another with no increase in the numnber elements.
|
|
|
Replicative Insertion
|
Where the reaction leads to the insertion of a copy of the original element into a second location leading to an increase in number of elements.
|
|
|
What happens when an element inserts onto a gene?
|
causes loss of function.
|
|
|
Transposase
|
An enzyme that catalyzes the transfer of the element from one positon to another and they are specific for their resepective repeats.
|
|
|
Inverted repeats
|
Are specifically recognized by the transposase usually <50 bp.
|
|
|
Direct repeats
|
Short repeats of the chromosomal target (insertion site) ususally <10 bp.
|
|
|
What type of bacteria are able to undergo Natural competence?
|
Gram +
|
