GENETICS UPDATED EXAM SCRIPT QUESTIONS AND
ANSWERS RATED A+
✔✔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
✔✔pedigree chart - ✔✔a diagram that shows the occurrence and appearance or
phenotypes of a particular gene or organism and its ancestors from one generation to
the next
✔✔chromatin - ✔✔unraveled and long DNA (during interphase)
, ✔✔chromosome - ✔✔condensed, coiled, and shorted DNA (this occurs during mitosis
and meiosis)
✔✔chromatids - ✔✔the two identical halves of a single replicated eukaryotic
chromosome and joined at the centromere
✔✔homologous chromosomes - ✔✔chromosome pairs of approximately the same
length, centromere position, and staining pattern, with genes for the same
characteristics at corresponding places (one homologous chromosome is inherited from
the mother; the other from the father)
✔✔daughter cells - ✔✔new cells
✔✔mitosis - ✔✔a type of cell division that results in two genetically identical daughter
cells each with the same number of chromosomes of the parent cell
✔✔meiosis - ✔✔a type of cell division that results in four genetically different daughter
cells each with half the number of chromosomes of the parent cell (also known as
reduction division)
✔✔sexual reproduction - ✔✔process by which two cells from different parent unite to
produce the first cell of a new organism
✔✔asexual reproduction - ✔✔process by which a single parent reproduces by itself
✔✔crossing over - ✔✔process in which homologous chromosomes exchange portions
of their chromatids during meiosis (also called gene shuffling)
✔✔genetic variation - ✔✔genetic differences within a species
✔✔fertilization - ✔✔a process in sexual reproduction in which a sperm unites with an
egg to make the first cell of a new organism, or zygote
✔✔zygote - ✔✔fertilized egg
✔✔somatic cell - ✔✔body cell (non-sex cell)
✔✔haploid (N) - ✔✔term used to refer to a cell that contains only a single set of
chromosomes and therefore only a single set of genes (Humans N = 23)
✔✔diploid (2N) - ✔✔term used to refer to a cell that contains both sets of homolgous
chromosomes (Humans 2N = 46)
ANSWERS RATED A+
✔✔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
✔✔pedigree chart - ✔✔a diagram that shows the occurrence and appearance or
phenotypes of a particular gene or organism and its ancestors from one generation to
the next
✔✔chromatin - ✔✔unraveled and long DNA (during interphase)
, ✔✔chromosome - ✔✔condensed, coiled, and shorted DNA (this occurs during mitosis
and meiosis)
✔✔chromatids - ✔✔the two identical halves of a single replicated eukaryotic
chromosome and joined at the centromere
✔✔homologous chromosomes - ✔✔chromosome pairs of approximately the same
length, centromere position, and staining pattern, with genes for the same
characteristics at corresponding places (one homologous chromosome is inherited from
the mother; the other from the father)
✔✔daughter cells - ✔✔new cells
✔✔mitosis - ✔✔a type of cell division that results in two genetically identical daughter
cells each with the same number of chromosomes of the parent cell
✔✔meiosis - ✔✔a type of cell division that results in four genetically different daughter
cells each with half the number of chromosomes of the parent cell (also known as
reduction division)
✔✔sexual reproduction - ✔✔process by which two cells from different parent unite to
produce the first cell of a new organism
✔✔asexual reproduction - ✔✔process by which a single parent reproduces by itself
✔✔crossing over - ✔✔process in which homologous chromosomes exchange portions
of their chromatids during meiosis (also called gene shuffling)
✔✔genetic variation - ✔✔genetic differences within a species
✔✔fertilization - ✔✔a process in sexual reproduction in which a sperm unites with an
egg to make the first cell of a new organism, or zygote
✔✔zygote - ✔✔fertilized egg
✔✔somatic cell - ✔✔body cell (non-sex cell)
✔✔haploid (N) - ✔✔term used to refer to a cell that contains only a single set of
chromosomes and therefore only a single set of genes (Humans N = 23)
✔✔diploid (2N) - ✔✔term used to refer to a cell that contains both sets of homolgous
chromosomes (Humans 2N = 46)
