GENETICS COMPREHENSIVE EXAM UPDATED QUESTIONS
AND ANSWERS RATED A+
✔✔trait - ✔✔a specific characteristic that varies from one individual to another
✔✔gene - ✔✔sequence of DNA that codes for a protein and thus determines a trait
✔✔genome - ✔✔the entire "library" of genetic instructions in DNA that an organism
inherits
✔✔Gregor Mendel - ✔✔father of genetics
✔✔allele - ✔✔alternative form of a gene (one member of a pair) located at a specific
position on a specific chromosome (a letter)
✔✔dominant allele - ✔✔an allele that produces the same phenotype whether its paired
allele is identical or different (capital letter)
✔✔recessive allele - ✔✔an allele that produces its characteristic phenotype only when
its paired allele is identical (lowercase letter)
✔✔genotype - ✔✔the combination of alleles located on homologous chromosomes that
determines a specific characteristic or trait (the allelic combination such as Bb)
✔✔phenotype - ✔✔the observable physical or biochemical characteristics of an
organism, as determined by the genotype (the expressed trait such as brown eyes)
✔✔homozygous - ✔✔term used to refer to an organism that has two identical alleles for
the same trait (ex. BB or bb)
✔✔heterozygous - ✔✔term used to refer to an organism that has two different alleles for
the same trait (ex. Bb)
✔✔Punnett square - ✔✔diagram showing the gene combinations that might result from
a genetic cross
✔✔gamete (sex cell) - ✔✔specialized cell involved in sexual reproduction (sperm or
egg)
✔✔probability - ✔✔the possibility of different outcomes (percentage or ratio)
✔✔monohybrid cross - ✔✔a one-trait cross (ex. color)
✔✔dihybrid cross - ✔✔a two-trait cross (ex. color & shape)
, ✔✔P generation - ✔✔parental generation is the first generation involving two individuals
that are mated to predict or analyze the genotypes of their offspring
✔✔F1 generation - ✔✔first filial generation is the generation resulting immediately from
a cross of the first set of parents (P generation)
✔✔F2 generation - ✔✔second filial generation is the generation resulting from a cross
between two F1 individuals
✔✔purebred - ✔✔offspring that are the result of mating between genetically similar
kinds of parents; opposite of hybrid; same as true breeding
✔✔hybrid - ✔✔offspring that are the result of mating between two genetically different
kinds of parents; opposite of purebred
✔✔Principle of Dominance - ✔✔when individuals with contrasting traits are crossed, the
offspring will express only the dominant trait
✔✔Law of Segregation - ✔✔states that allele pairs separate, or segregate, during
gamete formation
✔✔Law of Independent Assortment - ✔✔states that genes for different traits can
segregate independently during the formation of gametes
✔✔non-Mendelian inheritance - ✔✔refers to any pattern of inheritance in which traits do
not segregate in accordance with Mendel's laws (ex. incomplete dominance,
codominance, multiple alleles, polygenic traits, sex-linked traits)
✔✔incomplete dominance - ✔✔when one allele is not completely dominant over the
other, or blending occurs (ex. Red + White = Pink)
✔✔codominance - ✔✔occurs when BOTH alleles of a gene are expressed in an
individual (ex. Black + White = Black & White Speckled)
✔✔multiple allele traits - ✔✔traits that are controlled by more than two alleles (ex. ABO
blood typing = A allele, B allele, & O allele)
✔✔polygenic traits - ✔✔a trait controlled by two or more genes; produce a wide range
of phenotypes
✔✔sex-linked traits - ✔✔a trait genetically determined by an allele located on the sex
chromosome
AND ANSWERS RATED A+
✔✔trait - ✔✔a specific characteristic that varies from one individual to another
✔✔gene - ✔✔sequence of DNA that codes for a protein and thus determines a trait
✔✔genome - ✔✔the entire "library" of genetic instructions in DNA that an organism
inherits
✔✔Gregor Mendel - ✔✔father of genetics
✔✔allele - ✔✔alternative form of a gene (one member of a pair) located at a specific
position on a specific chromosome (a letter)
✔✔dominant allele - ✔✔an allele that produces the same phenotype whether its paired
allele is identical or different (capital letter)
✔✔recessive allele - ✔✔an allele that produces its characteristic phenotype only when
its paired allele is identical (lowercase letter)
✔✔genotype - ✔✔the combination of alleles located on homologous chromosomes that
determines a specific characteristic or trait (the allelic combination such as Bb)
✔✔phenotype - ✔✔the observable physical or biochemical characteristics of an
organism, as determined by the genotype (the expressed trait such as brown eyes)
✔✔homozygous - ✔✔term used to refer to an organism that has two identical alleles for
the same trait (ex. BB or bb)
✔✔heterozygous - ✔✔term used to refer to an organism that has two different alleles for
the same trait (ex. Bb)
✔✔Punnett square - ✔✔diagram showing the gene combinations that might result from
a genetic cross
✔✔gamete (sex cell) - ✔✔specialized cell involved in sexual reproduction (sperm or
egg)
✔✔probability - ✔✔the possibility of different outcomes (percentage or ratio)
✔✔monohybrid cross - ✔✔a one-trait cross (ex. color)
✔✔dihybrid cross - ✔✔a two-trait cross (ex. color & shape)
, ✔✔P generation - ✔✔parental generation is the first generation involving two individuals
that are mated to predict or analyze the genotypes of their offspring
✔✔F1 generation - ✔✔first filial generation is the generation resulting immediately from
a cross of the first set of parents (P generation)
✔✔F2 generation - ✔✔second filial generation is the generation resulting from a cross
between two F1 individuals
✔✔purebred - ✔✔offspring that are the result of mating between genetically similar
kinds of parents; opposite of hybrid; same as true breeding
✔✔hybrid - ✔✔offspring that are the result of mating between two genetically different
kinds of parents; opposite of purebred
✔✔Principle of Dominance - ✔✔when individuals with contrasting traits are crossed, the
offspring will express only the dominant trait
✔✔Law of Segregation - ✔✔states that allele pairs separate, or segregate, during
gamete formation
✔✔Law of Independent Assortment - ✔✔states that genes for different traits can
segregate independently during the formation of gametes
✔✔non-Mendelian inheritance - ✔✔refers to any pattern of inheritance in which traits do
not segregate in accordance with Mendel's laws (ex. incomplete dominance,
codominance, multiple alleles, polygenic traits, sex-linked traits)
✔✔incomplete dominance - ✔✔when one allele is not completely dominant over the
other, or blending occurs (ex. Red + White = Pink)
✔✔codominance - ✔✔occurs when BOTH alleles of a gene are expressed in an
individual (ex. Black + White = Black & White Speckled)
✔✔multiple allele traits - ✔✔traits that are controlled by more than two alleles (ex. ABO
blood typing = A allele, B allele, & O allele)
✔✔polygenic traits - ✔✔a trait controlled by two or more genes; produce a wide range
of phenotypes
✔✔sex-linked traits - ✔✔a trait genetically determined by an allele located on the sex
chromosome
