Upgrade to remove ads
ch 12 genetics
Terms in this set (63)
different forms of genes
only one copy is needed to express the trait (phenotype)
two copies are needed to express the trait (phenotype)
only one allele is present for that given gene
X chromosomes for males
a relationship in which one allele is completely dominant over another
A condition in which neither of two alleles of a gene is dominant or recessive; more than one dominant allele exists (ex. AB blood type, both A and B antigen expressed)
one allele is not completely dominant over another; the heterozygote expresses a phenotype intermediate of the dominant and recessive alleles (Ex. pink flowers made from white and red parent)
The percentage of individuals with a particular genotype that actually displays the phenotype associated with the genotype.
the degree to which a genotype is expressed in an individual; varying phenotypes despite identical genotype
all individuals with a given genotype express the same phenotype
individuals with the same genotype have related phenotypes that vary in intensity
Mendel's First Law: Law of Segregation
1. alleles account for variations in inherited characters 2. organisms inherit two copies of a gene, one from each parent 3. dominant allele determines appearance 4. each gamete only gets one allele (because they separate in meiosis)
what stage of meiosis correlates to mendel's law of segregation? (each gamete only gets one allele)
Mendel's Second Law: Law of Independent Assortment
the basis that each pair of alleles segregates independently of each other pair of alleles during gamete formation (ex/ whatever is in chromosome 1 won't affect the crossing over in chromosome 5)
At what stage of meiosis does crossing over occur?
All the genes, including all the different alleles for each gene, that are present in a population at any one time
flow of genes between species through hybrid offspring
wild type allele
The non-mutant form of a gene, encoding the normal genetic function. Generally, but not always a dominant allele.
one nucleotide in DNA is swapped for another
nucleotides in DNA
Adenine, Thymine, Guanine, Cytosine
alters one nucleotide but does not change the amino acid; no effect on final protein
A point mutation in which a codon that specifies an amino acid is mutated into a codon that specifies a different amino acid.
A mutation that changes an amino acid codon to one of the three stop codons, resulting in a shorter and usually nonfunctional protein.
mutation that shifts the "reading" frame of the genetic message by inserting or deleting a nucleotide
a mutation that involves duplication of a region of DNA on the same strand
A mutation involving a piece of a chromosome that breaks off and reattaches in reverse orientation.
occur when a segment of DNA is swapped with a segment of DNA from another chromosome
inborn errors of metabolism
defects in genes required for metabolism
A change in the allele frequency of a population as a result of chance events rather than natural selection.
change in allele frequencies as a result of the migration of a small subgroup of a population
Mating of organisms that are not closely related; this is a major mechanism of maintaining variation within a species
Parental generation, the first two individuals that mate in a genetic cross
Filial generation, offspring
A cross between individuals that involves one pair of contrasting traits
A cross between individuals that have different alleles for the same gene
genotypic ratio of heterozygote cross Pp x Pp
1:2:1 (1 PP 2 Pp 1pp)
phenotypic ratio of monohybrid heterozygote cross (Pp x Pp)
3:1...(3 express P trait 1 express p trait)
phenotypic ratio of heterozygote dihybrid cross (TtPp x TtPp)
9:3:3:1 (9 express T/P trait; 3 T/p; 3 P/t; 1 p/t)
likelihood that two alleles are separated from each other during crossing over
what is recombination proportional to
distance between the genes on the chromosome
One map unit between two genes indicates that crossing over occurs between them ____ percent of the time
how often an allele appears in a population
condition that occurs when the frequency of alleles in a particular gene pool remain constant over time, no evolution occurs
p^2 + 2pq + q^2 = 1 or p + q =1
What do p and q represent? in hardy-weinberg
p= frequency of dominant allele; q=frequency of recessive allele
What does p^2, 2pq, and q^2 represent? in hardy-weinberg
p^2= frequency of TT
2pq= frequency of Tt
q^2= frequency of tt
A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.
Traits that enhance an organism's reproductive success.
Are natural selection and evolution the same thing?
no! natural selection is a mechanism of evolution <3
an evolutionary theory proposing that mutations produce variations and that natural selection determines which variations will survive in order to produce biological evolution
The total effect an individual has on proliferating its genes by producing its own offspring and by providing aid that enables other close relatives to increase the production of their offspring.
Pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change
Natural selection that favors intermediate variants by acting against extreme phenotypes
Form of natural selection in which the entire curve moves; occurs when individuals at one end of a distribution curve have higher fitness than individuals in the middle or at the other end of the curve
form of natural selection in which a single curve splits into two; occurs when individuals at the upper and lower ends of a distribution curve have higher fitness than individuals near the middle
evolution from a common ancestor of many species adapted to diverse environments
Formation of new species
mating and fertilization are prevented (no zygote formed)
mating occurs, but offspring are sterile or inviable
when two or more species sharing a common ancestor become more different over time
Two related species that have made similar evolutionary adaptations after their divergence from a common ancestor
Evolution toward similar characteristics in unrelated species
molecular clock model
the degree of difference in the genome between two species is related to the amount of time since the two species broke off from a common ancestor
THIS SET IS OFTEN IN FOLDERS WITH...
biology chapter 1 and 2
biology chapter 3
biology chapter 4
biology chapter 5
OTHER SETS BY THIS CREATOR
ch 6 equilibrium
ch 5 kinetics
chemistry ch 3 bonds and ch4 compounds/s…