BIO 1201 GREGG EXAM CORE QUESTIONS WITH
SOLUTIONS GRADED A+2025/2026
✔✔occurs when phenotypes of the heterozygote and dominant homozygote are
identical - ✔✔complete dominance
✔✔the phenotype of F1 hybrids is somewhere between the phenotypes of the two
parental varieties - ✔✔incomplete dominance
✔✔two dominant alleles affect the phenotype in separate, distinguishable ways -
✔✔codominance
✔✔when one gene has multiple phenotypic effects - ✔✔pleiotropy
✔✔what hereditary diseases are caused by pleiotropic alleles - ✔✔cystic fibrosis and
sickle-cell disease
✔✔when expression of a gene at one locus alters the phenotypic expression of a gene
at a second locus - ✔✔epistasis
✔✔when multiple genes independently affect a single trait - ✔✔polygenic inheritance
✔✔example of epistasis - ✔✔labrador retriever coat color: one gene determines the
pigment color and the other gene determines if the pigment is deposited in the hair
✔✔example of polygenic inheritance - ✔✔over 180 genes affect height
✔✔heterozygous individuals who carry the recessive allele but are phenotypically
normal - ✔✔carriers
✔✔recessive disorders show up only in individuals ____ - ✔✔homozygous for the allele
✔✔example of recessive disorder - ✔✔albinism
✔✔example of dominant disorder - ✔✔achondroplasia (dwarfism)
✔✔degenerative disease of the nervous system - ✔✔Huntington's disease (has no
effect until the individual is 40 years of age)
✔✔someone with two x chromosomes is a ___ - ✔✔female
✔✔someone with one x and one y chromosome is a ___ - ✔✔male
, ✔✔a gene that is located on either sex chromosome is called a - ✔✔sex-linked gene
✔✔is the x or the y chromosome bigger - ✔✔x
✔✔disorders caused by recessive alleles on the x chromosome in humans are... -
✔✔color blindness, duchenne muscular dystrophy, hemophilia, male pattern baldness
✔✔x inactivation - ✔✔-in females, one of the X chromosomes is randomly inactivated,
and forms a Barr Body
✔✔genes that are located on the same chromosome tend to be inherited together and
are called... - ✔✔linked genes
✔✔pairs of homologous chromosomes do not separate normally during meiosis -
✔✔nondisjunction
✔✔results from the fertilization of gametes in which nondisjunction occurred -
✔✔aneuploidy
✔✔a condition in which an organism has more than two complete sets of chromosomes
- ✔✔polyploidy
✔✔removes a chromosomal fragment - ✔✔deletion
✔✔repeats a segment - ✔✔duplication
✔✔reverses orientation of a segment within a chromosome - ✔✔inversion
✔✔moves a segment from one chromosome to another - ✔✔translocation
✔✔an aneuploid condition that results from three copies of chromosome 21 - ✔✔down
syndrome
✔✔the result of an extra chromosome in a male, producing XXY individuals -
✔✔klinefelter syndrome
✔✔turner syndrome - ✔✔monosomy X, sterile females
✔✔when the phenotype depends on which parent passed along the alleles for the trait -
✔✔genomic imprinting
✔✔change in genotype and phenotype due to assimilation of foreign DNA -
✔✔transformation
SOLUTIONS GRADED A+2025/2026
✔✔occurs when phenotypes of the heterozygote and dominant homozygote are
identical - ✔✔complete dominance
✔✔the phenotype of F1 hybrids is somewhere between the phenotypes of the two
parental varieties - ✔✔incomplete dominance
✔✔two dominant alleles affect the phenotype in separate, distinguishable ways -
✔✔codominance
✔✔when one gene has multiple phenotypic effects - ✔✔pleiotropy
✔✔what hereditary diseases are caused by pleiotropic alleles - ✔✔cystic fibrosis and
sickle-cell disease
✔✔when expression of a gene at one locus alters the phenotypic expression of a gene
at a second locus - ✔✔epistasis
✔✔when multiple genes independently affect a single trait - ✔✔polygenic inheritance
✔✔example of epistasis - ✔✔labrador retriever coat color: one gene determines the
pigment color and the other gene determines if the pigment is deposited in the hair
✔✔example of polygenic inheritance - ✔✔over 180 genes affect height
✔✔heterozygous individuals who carry the recessive allele but are phenotypically
normal - ✔✔carriers
✔✔recessive disorders show up only in individuals ____ - ✔✔homozygous for the allele
✔✔example of recessive disorder - ✔✔albinism
✔✔example of dominant disorder - ✔✔achondroplasia (dwarfism)
✔✔degenerative disease of the nervous system - ✔✔Huntington's disease (has no
effect until the individual is 40 years of age)
✔✔someone with two x chromosomes is a ___ - ✔✔female
✔✔someone with one x and one y chromosome is a ___ - ✔✔male
, ✔✔a gene that is located on either sex chromosome is called a - ✔✔sex-linked gene
✔✔is the x or the y chromosome bigger - ✔✔x
✔✔disorders caused by recessive alleles on the x chromosome in humans are... -
✔✔color blindness, duchenne muscular dystrophy, hemophilia, male pattern baldness
✔✔x inactivation - ✔✔-in females, one of the X chromosomes is randomly inactivated,
and forms a Barr Body
✔✔genes that are located on the same chromosome tend to be inherited together and
are called... - ✔✔linked genes
✔✔pairs of homologous chromosomes do not separate normally during meiosis -
✔✔nondisjunction
✔✔results from the fertilization of gametes in which nondisjunction occurred -
✔✔aneuploidy
✔✔a condition in which an organism has more than two complete sets of chromosomes
- ✔✔polyploidy
✔✔removes a chromosomal fragment - ✔✔deletion
✔✔repeats a segment - ✔✔duplication
✔✔reverses orientation of a segment within a chromosome - ✔✔inversion
✔✔moves a segment from one chromosome to another - ✔✔translocation
✔✔an aneuploid condition that results from three copies of chromosome 21 - ✔✔down
syndrome
✔✔the result of an extra chromosome in a male, producing XXY individuals -
✔✔klinefelter syndrome
✔✔turner syndrome - ✔✔monosomy X, sterile females
✔✔when the phenotype depends on which parent passed along the alleles for the trait -
✔✔genomic imprinting
✔✔change in genotype and phenotype due to assimilation of foreign DNA -
✔✔transformation
