GB 370 GENTRY COMPREHENSIVE EXAM 2025/2026
QUESTIONS AND ANSWERS GRADED A+
✔✔Complete dominance - ✔✔a relationship in which one allele is completely dominant
over another. Masks the recessive allele. Purple flower dominant to white
✔✔Incomplete dominance - ✔✔A pattern of inheritance in which two alleles, inherited
from the parents, are neither dominant nor recessive. The resulting offspring have a
phenotype that is a blending of the parental traits. Red, pink and white flowers
✔✔Codominance - ✔✔both alleles are expressed- AB blood types.
✔✔Sex linked - ✔✔genes found on only one sex chromosome, not both-
colorblindness.
✔✔Sex-influenced - ✔✔phenomenon in which an allele is dominant in one sex but
recessive in the opposite sex. - male pattern baldness, horns in sheep.
✔✔sex limited - ✔✔A trait occurs in only one of the sexes.- beardr growth in males.
✔✔Nondisjunction - ✔✔Chromosomes do not segregate properly- down syndrome.
✔✔Lyon hypothesis - ✔✔in females with XX genotype, one X is inactivated after zygote
formed during embryonic development
✔✔Promoter vs enhancer - ✔✔Promoter- site to begin transcription.
Enhancer- make the effects of transcription greater.
✔✔Transition mutation - ✔✔purine to purine or pyrimidine to pyrimidine
✔✔Transversion mutation - ✔✔A point mutation in which a pyrimidine is substitued for a
purine, or vice versa.
✔✔Which is more common: transition or transversion mutation - ✔✔A to G or C to T
mutations are preferred molecularly whith DNA replication.
✔✔Wobble theory - ✔✔explains why the third amino acid can (sometimes) change but
still produce the same amino acid; there is some "wiggle room" in tRNA that allows it to
still bring the correct amino acid
✔✔How is the genetic code both universal and degenerate? - ✔✔Universal- same 3
codons generally code for same amino acids.
Degenerate- multiple different codons can specify the same amino acid, allowing for
redundancy as well as buffer for mutation
, ✔✔3 ways RNA processed in eukaryotes - ✔✔5' cap, poly A tail, Intron splicing to allow
exons to join together.
✔✔Base Excision Repair (BER) - ✔✔Abnormal base/nucleotide recognized and
removed from DNA, segment is excised, complementary DNA strands become template
to synthesize normal DNA strand.
✔✔Mismatch Repair- DNA - ✔✔Base pair mismatch, recognized, segment in the area is
taken out. Parental strand used as template to synthesize normal daughter DNA strand.
✔✔Homologous recombination repair - ✔✔happens at double strand breaks/when DNA
damage causes gap in synthesis during DNA replication. Normal sister chromatid
strands repairs damaged SC.
✔✔Pedigree - ✔✔A diagram that shows the occurrence of a genetic trait in several
generations of a family.
✔✔Population - ✔✔A group of individuals that belong to the same species and live in
the same area
✔✔Gene flow - ✔✔Individuals migrate from one population to another, migrants are
able to breed successfully with members of recipient population.
✔✔3 requirements for Hardy-Weinberg equilibrium - ✔✔No mutations, no gene flow,
large population size, random mating, no natural selection
✔✔Genetic drift - ✔✔change in allele frequencies in a population size due to random
fluctuations- reduces genetic diversity, and increases chance of inbreeding.
✔✔Founder effect - ✔✔Genetic drift that occurs when a few individuals become isolated
from a larger population and form a new population whose gene pool composition is not
reflective of that of the original population.- reduced genetic diversity, increases
frequency of certain traits/disorders.
✔✔Bottleneck effect - ✔✔A change in allele frequency following a dramatic reduction in
the size of a population- makes population more vulnerable to disease and climate
change, less genetic variation.
✔✔Linkage - ✔✔genes that are close together on the same chromosome tend to be
transmitted as a unit.
✔✔If two genes are completely linked, how many types of gametes will be seen? -
✔✔2. Same combinations as parents
QUESTIONS AND ANSWERS GRADED A+
✔✔Complete dominance - ✔✔a relationship in which one allele is completely dominant
over another. Masks the recessive allele. Purple flower dominant to white
✔✔Incomplete dominance - ✔✔A pattern of inheritance in which two alleles, inherited
from the parents, are neither dominant nor recessive. The resulting offspring have a
phenotype that is a blending of the parental traits. Red, pink and white flowers
✔✔Codominance - ✔✔both alleles are expressed- AB blood types.
✔✔Sex linked - ✔✔genes found on only one sex chromosome, not both-
colorblindness.
✔✔Sex-influenced - ✔✔phenomenon in which an allele is dominant in one sex but
recessive in the opposite sex. - male pattern baldness, horns in sheep.
✔✔sex limited - ✔✔A trait occurs in only one of the sexes.- beardr growth in males.
✔✔Nondisjunction - ✔✔Chromosomes do not segregate properly- down syndrome.
✔✔Lyon hypothesis - ✔✔in females with XX genotype, one X is inactivated after zygote
formed during embryonic development
✔✔Promoter vs enhancer - ✔✔Promoter- site to begin transcription.
Enhancer- make the effects of transcription greater.
✔✔Transition mutation - ✔✔purine to purine or pyrimidine to pyrimidine
✔✔Transversion mutation - ✔✔A point mutation in which a pyrimidine is substitued for a
purine, or vice versa.
✔✔Which is more common: transition or transversion mutation - ✔✔A to G or C to T
mutations are preferred molecularly whith DNA replication.
✔✔Wobble theory - ✔✔explains why the third amino acid can (sometimes) change but
still produce the same amino acid; there is some "wiggle room" in tRNA that allows it to
still bring the correct amino acid
✔✔How is the genetic code both universal and degenerate? - ✔✔Universal- same 3
codons generally code for same amino acids.
Degenerate- multiple different codons can specify the same amino acid, allowing for
redundancy as well as buffer for mutation
, ✔✔3 ways RNA processed in eukaryotes - ✔✔5' cap, poly A tail, Intron splicing to allow
exons to join together.
✔✔Base Excision Repair (BER) - ✔✔Abnormal base/nucleotide recognized and
removed from DNA, segment is excised, complementary DNA strands become template
to synthesize normal DNA strand.
✔✔Mismatch Repair- DNA - ✔✔Base pair mismatch, recognized, segment in the area is
taken out. Parental strand used as template to synthesize normal daughter DNA strand.
✔✔Homologous recombination repair - ✔✔happens at double strand breaks/when DNA
damage causes gap in synthesis during DNA replication. Normal sister chromatid
strands repairs damaged SC.
✔✔Pedigree - ✔✔A diagram that shows the occurrence of a genetic trait in several
generations of a family.
✔✔Population - ✔✔A group of individuals that belong to the same species and live in
the same area
✔✔Gene flow - ✔✔Individuals migrate from one population to another, migrants are
able to breed successfully with members of recipient population.
✔✔3 requirements for Hardy-Weinberg equilibrium - ✔✔No mutations, no gene flow,
large population size, random mating, no natural selection
✔✔Genetic drift - ✔✔change in allele frequencies in a population size due to random
fluctuations- reduces genetic diversity, and increases chance of inbreeding.
✔✔Founder effect - ✔✔Genetic drift that occurs when a few individuals become isolated
from a larger population and form a new population whose gene pool composition is not
reflective of that of the original population.- reduced genetic diversity, increases
frequency of certain traits/disorders.
✔✔Bottleneck effect - ✔✔A change in allele frequency following a dramatic reduction in
the size of a population- makes population more vulnerable to disease and climate
change, less genetic variation.
✔✔Linkage - ✔✔genes that are close together on the same chromosome tend to be
transmitted as a unit.
✔✔If two genes are completely linked, how many types of gametes will be seen? -
✔✔2. Same combinations as parents
