mutation mod31 Flashcards
the 2 types of mutation
changes in chromosome number and point mutation
what is a mutant
someone who exhibits a special phenotype
recombination mechanisms do what
rearrange genetic variability into new combinations
natural selection preserves what
the combinations best adapted to existing environment
Germinal mutations occur
1) in what cells
2) how do they affect progeny
1) germ line cells
2) transmitted though the gametes to the progeny
Somatic mutations occur
1) in what cells and phenotype will only occur in what
2) affect progeny how
1) somatic cells, mutant phenotype will occur only in the descendants of that cell
2) not be transmitted to the progeny
Spontaneous summations occur and are frequent or infrequent
occur without a known cause due to inherent metabolic errors or unknown agents in the environment
Infrequent
Induced mutations result from
from exposure or organisms to mutagens, physical and chemical agents that cause changes in DNA, such as ionizing irradiation, ultraviolet light, or certain chemicals
Is mutation random
yes
is muation non adaptive
yes
does environmental stress cause mutations
No, selects mutants best adapted to environmental stress
when does mutagenesis occur inbacteria
when populations of bacteria stop growing (in stationary growth phrase)
increase in mutagenesis is due to induction of what
error prone dna repair processes
adapted mutation is NOT equal to what
direct mutation
Forward muation is
wild type allele to a mutant allele
reverse mutation is what
second mutation that restores the original phenotype
Back mutation is what
second mutation at the same siite
Suppresor mutatoin is what
second mutation at a different location in the genome
The progeny will have what phenotype if its a back mutation
All progeny will have the wild type phenotype
The progeny will have what progeny if its a supressor mutation
some of the progeny will have the mutant phenotype
How to distinguish between supressor and back mutation
backcross the phenotypic revertant with the wild-type
In diploids, most recessive mutations will not be what but what is an exception
not be recognised but X linked recessive mutations are an exception
What are neutral mutations
when the mutations have no effect on the phenotype
X linked recessive lethal mutations alter what ratio
sex ratio because the mutation will cause one progeny to die
Recessive mutations often block what
metabolic pathways
How can recessive mutations affect metabolic pathway
Enzymes are encoded by genes, alterations of these genes then means the enzyme is changed which affects metabolic pathways
Hemoglobin mutation leads to sickle cell anemia, what is the mutation
6th amino acid in hemoglobin S is valine when it should be glutamic acid.
Mutation is of single bae pair
Tay sachs is what type of disease and what is the mutation
autosomal recessive disease, gene encoding hexosaminidase A
Conditional lethal mutations are what (2 things)
lethal in restrictive conditions but viable in the permissive coondition
mutants with conditional lethal alleles can be propagated under what conditions and the phenotype can be studied under what conditions
proagated under the permissive condition and studied under restrictive conditions
what are the 3 major types of lethal conditions
auxotrophs, temp sensitive and suppressor sensitive
how are conditional lethal mutations used to study biological pathways
intermediate is allowed to form and then the mutation will prevent the prevent from being made and so the process can be seen
