genetics exam 4 Flashcards
mutation where a single base pair is changed
point mutation
mutation where a large portion of chromosomes are affected
large scale mutation
mutation where pyrimidine ->pyrimidine or purine->purine
transitions
mutation where purine ->pyrimidine or vice versa
transversion
change in a reproductive cell, like an egg or sperm
germ line
a change in DNA that happens in any cell except reproductive cells
somatic
change in base produces same amino acid as before
silent mutations
a change in a gene’s DNA that replaces an amino acid with a different one
missense mutation
insertions and deletions, not multiple of 3 bases; DNA sequence is inserted or deleted by a number of nucleotides; shifts entire genome
frameshift mutation
the result is a shift of all genetic material because one base is added or removed, altering the entire genome
insertions or deletions
base change initiated a premature stop codon
nonsense mutation
mutations that occur naturally
spontaneous
mutations that are caused by exposure to external factors
induced
anything that induces a higher rate of mutation than the spontaneous rate of mutation
mutagen
mutagens such as x-rays, gamma rays, UV light
radiation
mutagen such as base analogs or intercalating agents
chemicals
mutagen such as viruses or bacteria
biological agents
mutations can be induced to identify genes that are involved in particular processes (ex: stickleback fish)
genetic dissection
molecular basis for spontaneous mutations here nitrogenous bases pair with atypical bases
tautomers
molecular bases for spontaneous mutations due to the splitting of repetitive DNA during replications
streisinger model for duplications and deletions
loss of purine base from DNA strand
depurination
conversion of cytosine to uracil
deamination
molecular basis for induced mutations where ____ can pair with different bases depending on their chemical form
base analogs
molecular bases for induced mutations where ___ insert between adjacent bases and distort the structure of DNA
intercalating agents
induces pyrimidine dimers (covalent bonds between adjacent Ts)
UV light
produces highly reactive oxygen species that chemically alter DNA bases
ionizing radiation
what results from the disruption of the normal balance between cell proliferation and cell death and is essentially a disease of cell numbers
cancer
___ act as regulatory subunits that bind to and activate cyclin-dependent kinases, which then phosphorylate specific target proteins at different stages of the cell cycle, triggering the necessary transition between G1 to S or G2 to M
cyclin
___ activates the cyclin-dependent Rb protein, allowing for the transcription of genes necessary for DNA replication to proceed
Cyclin E pathway
how ___ stimulates cell proliferation; binds to its specific receptor on the cell membrane, which triggers a cascade of genes involved in cell division
insulin-like growth factor (IGF-I)
key step in initiating cell cycle progression; induces genes in the mitogen-activated protein kinase pathway
activation of intracellular signaling
programmed cell death, a cell self-destructs as part of normal biological function
apoptosis
1) increasing the activity of a growth-promoting protein 2) causing the protein to be produced in abnormally high quantities
mutations in oncogenes
recombination occurs during ___ where homologous chromosomes pair up and exchange genetic material through a process called crossing over
prophase I
inversions and translocations
chromosome rearrangements
deletions and duplications
nitrogenous base variations
genetic process where DNA strands can break at random locations on a chromosome, the broken pieces can then rejoin with segments from another chromosome
chromosomal translocation
crossover between repetitive DNA sequences that are found at different sited throughout the genome
unequal crossover
when 2 different chromosomes exchange pieces of genetic material with each other
reciprocal translocations
when the entire long arms of two acrocentric chromosomes fuse together, creating a single large chromosome
Robertsonian translocations
variation in the number of complete sets of chromosomes; monoploid, haploid, diploid, and polyploids
euploidy
individuals who do not have complete sets of chromosomes (missing or extra); nullisomic, monosomic, trisomic
aneuploidy
turner syndrome, klinefelter syndrome, downs syndrome, and Edwards syndrome
human aneuploids
study of genetic variation in populations and factors that cause changes in genetic variation
population genetics
___ is a measure of genetic variation in individuals and populations
heterozygosity
HW equilibrium applies when certain conditions are met;
large population size, random mating, no mutation, no migration, discrete generations, no selection
how ___ can change alleles and genotype frequencies by favoring individuals with certain advantageous alleles, allowing them to survive and reproduce more successfully
natural selection
conditions required for microevolution by natural selection
variation within a population, heritable traits, differential reproduction, time for traits to become prevalent
