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a base substitution mutation
alters a single codon
Adaption
change over time in flora and fauna
allopatric
chipmunks separated by grand cannon
Alternative splicing
when different exons are joined to create different gene sequences
base insertion/deletion mutation
an insertion or deletion that alters the reading frame and may change many codons
bottleneck effect
examples are hunting a population into an endangered species threatening extinction
constitutive expression
continuously expressed under normal cellular conditions
constitutive expression
continuously expressed under normal cellular conditions
Directional selection
changes in allele frequency over time example- brain size
Disruptive selection
extremes benefit: small hide, medium get eaten, large dominate
Exons
expressed sequence of DNA; codes for a protein
founder effect
a group from a population relocate and form a new population
frame shift mutation
insertion or deletion of one or 2 nucleotides
gene flow
introducing a new gene to a population
Genetic drift
leads to homozygosity -allele fixation leaving the population with little to no variation
germ cell mutations
-Heritable; basis for the transmission of genetic diversity and evolution, as well as genetic diseases
How does the lactose operon work?
If there is no lactose present then it doesn't need to be turned on
how does the tryptophan operon work?
It is always on and if there is too much tryptophan present than the repressor can bind
induced mutations
result from an extraneous factor such as radiation, UV light, and natural & synthetic chemicals
Inducible operons
transcription is usually off and needs to be turned on
Introns
non-coding sequences
missense mutation
produces a different amino acid
morphological concepts
how to look at something and see its differences
Mutation
an alteration in DNA sequence
negative control
inhibit gene expression
Negative indicible
-normally off
-repressor in active form
negative repressible
-usually on
-product turns on repressor.
negative selection
allele has negative effect - DECREASES frequency
neutral mutation
no change in function
nonsense mutation
changes an amino acid codon to stop codons, resulting in a shorter and usually nonfunctional protein.
Operator
controls if RNA polymerase can bind + how often
Operon
group of structural genes under control of promotor
Peripatric
spruce trees from glacier
positive control
stimulate gene expression
Positive inducible
-usually off
-substrate will initiate activator
Positive Repressible
-usually on
-inactivating the activator
positive selection
an allele gives an advantage - INCREASES frequency in population
Regulator genes
activators and repressors
Regulatory elements
DNA sequences that are not transcribed but play a role in regulating other nucleotide sequences
regulatory genes
encoding proteins or RNAs that interact with other sequences
Repressible operons
Transcription is normally on and needs to be turned off
Reverse mutation
mutant type to wild type (fixes it)
ring species
closely related
silent mutation
change in amino acids
Gene may remain the same
somatic
non-reproductive cells
spontaneous mutations
happen naturally and randomly and are usually linked to normal biological or chemical processes in the organism
Stabilizing selection
intermediates thrive - example: baby weight
structural genes
encoding proteins
Transcription factors
sequence specific DNA binding proteins
what 3 things effect initiation of transcription ?
-Basal transcription apparatus
-Regulatory transcription factor
-Promotor
what is an example of a gain of function mutation
cancer causing genes effecting cell division
What is polyadenylation?
when a cap is placed on one end to stabilize and a poly A tail is attached to the other side
What is the Shine-Dalgarno sequence?
a sequence recognized by a ribosome that is paired with an AUG codon to initiate translation
What is the TATA box ?
transcription start site
