BIO Chapter 11 Quiz

gene

characteristic (located on chromosome)

allele

variation of gene

dominant

presents itself in heterozygote

recessive

dormant in heterozygote

homozygous

carries 2 of the same alleles (BB or bb)

heterozygous

carries 2 different alleles (Bb)

genotype

your genes (cannot see)

phenotype

physical characteristic/expression (can see)

monohybrid

crossing 1 trait (Bb x bb)

law of segregation

each pair of alleles separates independently from other pairs during gamete formation (so each allele has an equal chance of being passed on)

law of independent assortment

genes for different traits don't always line up the same at metaphase I

complete dominance

occurs when phenotypes of heterozygote and dominant homozygote are identical
ex: eye color

codominance

2 dominant alleles affect phenotype in separate, distinguishable ways
ex: human blood group AB

incomplete dominance

phenotype of hybrids is somewhere between 2 parental varieties (BLEND)
ex: flower color (red + white = pink)

multiple alleles

most genes exist in populations; 2+ allelic forms
ex: ABO blood group

polygenic

traits are determined by 2 or more genes; added effect on single phenotype (RANGE)
ex: hair color, height

sex linked

genes of characteristics that are related to sex; males cannot carry
ex: colorblindness, hemophilia

nondisjunction

pairs of homologous chromosomes don't separate normally in meiosis; therefore, gametes contain 2 copies/no copies of chromosome
ex: down syndrome

nonnuclear inheritance

chloroplasts and mitochondria are randomly assorted to gametes and daughter cells; don't always follow Mendelian rules
- mitochondrial: determined traits are maternally inherited

phenotypic plasticity

when individuals with the same genotype exhibit different phenotypes in different environments
ex: flower color in soil pH, fur color in arctic mammals

linked genes

adjacent and close to each other on same chromosome (move together as unit)

recombinant offspring

show new combinations of parental traits