Module 1 Flashcards
Phenotype
the visible properties of a mutant
Genotype
the specific allele composition of a cell
Mutation
a heritable change to the sequence of DNA molecule
Wild type
the initial “non-mutant” organism
A mutant
an organisms carrying a mutation
Forward mutation
a loss of function mutation that generates a mutant organism from a wild type one
Reversion
a mutational event that converts a mutant organism back into a wild one
Auxotroph
a micro-organism that can only grow in the presence off a specific growth supplements such as amino acids
Point mutation
a mutation at a single point (often a single base pair)
Substitution mutation
a mutation where one base pair in the DNA sequence is changed to another
Frameshift
a base pair DNA is incorporated into, or are lost from, a gene
Deletion Mutation
one or more base pair of DNA are lost from a gene
insertion mutation
one or more base pairs of DNA are inserted into a gene
Spontaneous mutation
a mutation that occurs in the absence of any mutagen or other external causes
Lesion
In DNA, a chemical change (damage); this is not a mutation but can lead into mutation
his+
does not require histidine for growth; denoted His+
his or hisG
requires histidine for growth; denoted His-
lac+
can use lactose as a source for energy; denoted Lac+
lac or lacZ
cannot use lactose as a source of energy; denoted Lac-
Bacteriophage
A virus that infects bacteria
Fluctuation test
a test used in microbes to establish the random nature of mutation or to measure mutation rates
Ames test
Test in which special stains of bacteria are used to evaluate the potential of chemicals to cause cancer
Bacteriophage plaques
these are holes in lawn of bacteria where the bacteria have been killed by the phage
Haploid
the presence of a single set of chromosome in an organism’s cell
Complementation
production of a wild type phenoty
wild type
genes that predominates in the natural population of organisms
Indels
insertion of deletion of one or more nucleotides in a DNA base sequence
complementation
production of wild type phenotype when two mutant haploid genomes bearing recessive mutations are present in the same cell
Recombination
a process that results in new combinations of mutations (i.e. progeny is genetically different to parents)
complementation
tells you if the mutation are in the same or different genes; progeny are genetically identical to parents
Tautomerization of Bases
A base transiently flips into a different isomer that has different base pairing properties (a cause of mutations)
DNA proofreading
- Reduces spontaneous mutations
- Works by DNA polymerase checking each newly synthesized base pair in a strand of DNA. If it has made a mistake it backs up, removes the incorrect base and then resumes the synthesis of DNA
Mismatch Repair System
- detects mismatched base pairs in DNA molecules
- Distinguishes correct and incorrect strands of DNA
