BIOD 210 GENETICS FINAL EXAM QUESTIONS
AND ANSWERS () (VERIFIED
ANSWERS)
This comprehensive exam is designed to mirror the curriculum of BIOD 210 (Genetics). It
covers fundamental principles, molecular mechanisms, and modern applications of genetic
science.
BIOD 210: Genetics Final Examination (2026/2027)
Table of Contents
1. Section 1: Mendelian Genetics and Inheritance Patterns (Questions 1-20)
2. Section 2: DNA Structure, Replication, and Repair (Questions 21-40)
3. Section 3: Transcription, Translation, and Gene Regulation (Questions 41-60)
4. Section 4: Cytogenetics and Chromosomal Mutations (Questions 61-75)
5. Section 5: Molecular Genetic Technologies (Questions 76-90)
6. Section 6: Population and Quantitative Genetics (Questions 91-100)
Section 1: Mendelian Genetics and Inheritance Patterns
1. Who is considered the father of modern genetics?
• Answer: Gregor Mendel.
• Rationale: Mendel’s work with pea plants in the 1860s established the fundamental laws
of inheritance (Segregation and Independent Assortment).
2. A cross between a homozygous dominant (AA) and a homozygous recessive (aa) results in
what phenotypic ratio in the F2 generation?
• Answer: 3:1.
• Rationale: The F1 are all Aa. Crossing Aa x Aa results in 1 AA, 2 Aa, and 1 aa. Since AA
and Aa show the dominant phenotype, the ratio is 3 dominant to 1 recessive.
3. Define "Allele."
, • Answer: An alternative form of a gene.
• Rationale: Genes can have different versions (e.g., blue eyes vs. brown eyes) located at
the same locus on homologous chromosomes.
4. What is a "Test Cross"?
• Answer: Crossing an individual with a dominant phenotype but unknown genotype with
a homozygous recessive individual.
• Rationale: If any offspring show the recessive phenotype, the parent was heterozygous;
if all show the dominant phenotype, the parent was likely homozygous dominant.
5. What is Incomplete Dominance?
• Answer: A pattern where the heterozygote displays an intermediate phenotype between
the two homozygotes.
• Rationale: In snapdragons, crossing red (RR) and white (rr) produces pink (Rr) because
neither allele is completely dominant.
6. Define Codominance.
• Answer: A condition where both alleles in a heterozygote are fully expressed.
• Rationale: In AB blood types, both the A and B antigens are present on the red blood cell
surface.
7. Mendel’s Law of Segregation states that:
• Answer: The two alleles for a heritable character separate during gamete formation and
end up in different gametes.
• Rationale: This ensures that each gamete carries only one allele for each gene.
8. What is the phenotypic ratio of a Mendelian dihybrid cross (AaBb x AaBb)?
• Answer: 9:3:3:1.
• Rationale: This represents the distribution of two independent traits following the law of
independent assortment.
9. Define Epistasis.
• Answer: One gene masks or interferes with the expression of another gene.
• Rationale: In coat color of Labradors, one gene determines pigment color, but another
gene determines if that pigment is actually deposited in the hair.
10. What is Pleiotropy?
, • Answer: When a single gene affects multiple, seemingly unrelated phenotypic traits.
• Rationale: Cystic fibrosis is pleiotropic because one gene mutation affects the lungs,
pancreas, and sweat glands.
11. In a pedigree, a filled-in square represents what?
• Answer: An affected male.
• Rationale: Squares represent males, circles represent females, and shading indicates the
presence of the trait/disorder.
12. If a trait skips generations and affects both males and females, it is likely:
• Answer: Autosomal Recessive.
• Rationale: Recessive traits can be carried silently by heterozygotes; autosomal means it
isn't linked to sex chromosomes.
13. What is Polygenic Inheritance?
• Answer: The determination of a particular characteristic by many genes.
• Rationale: Traits like human skin color or height show a continuous gradient because
they are influenced by multiple loci.
14. What is a "Locus"?
• Answer: The specific physical location of a gene on a chromosome.
• Rationale: Each gene occupies a fixed position, which is consistent across members of
the same species.
15. If a woman is a carrier for Hemophilia (X-linked recessive) and marries a normal male,
what is the chance their son will have hemophilia?
• Answer: 50%.
• Rationale: The son receives a Y from the father and either the normal X or the mutant X
from the mother.
16. Define Hemizygous.
• Answer: Having only one copy of a gene in a diploid organism.
• Rationale: Human males are hemizygous for genes on the X chromosome because they
only have one X.
17. What is the "Norm of Reaction"?
AND ANSWERS () (VERIFIED
ANSWERS)
This comprehensive exam is designed to mirror the curriculum of BIOD 210 (Genetics). It
covers fundamental principles, molecular mechanisms, and modern applications of genetic
science.
BIOD 210: Genetics Final Examination (2026/2027)
Table of Contents
1. Section 1: Mendelian Genetics and Inheritance Patterns (Questions 1-20)
2. Section 2: DNA Structure, Replication, and Repair (Questions 21-40)
3. Section 3: Transcription, Translation, and Gene Regulation (Questions 41-60)
4. Section 4: Cytogenetics and Chromosomal Mutations (Questions 61-75)
5. Section 5: Molecular Genetic Technologies (Questions 76-90)
6. Section 6: Population and Quantitative Genetics (Questions 91-100)
Section 1: Mendelian Genetics and Inheritance Patterns
1. Who is considered the father of modern genetics?
• Answer: Gregor Mendel.
• Rationale: Mendel’s work with pea plants in the 1860s established the fundamental laws
of inheritance (Segregation and Independent Assortment).
2. A cross between a homozygous dominant (AA) and a homozygous recessive (aa) results in
what phenotypic ratio in the F2 generation?
• Answer: 3:1.
• Rationale: The F1 are all Aa. Crossing Aa x Aa results in 1 AA, 2 Aa, and 1 aa. Since AA
and Aa show the dominant phenotype, the ratio is 3 dominant to 1 recessive.
3. Define "Allele."
, • Answer: An alternative form of a gene.
• Rationale: Genes can have different versions (e.g., blue eyes vs. brown eyes) located at
the same locus on homologous chromosomes.
4. What is a "Test Cross"?
• Answer: Crossing an individual with a dominant phenotype but unknown genotype with
a homozygous recessive individual.
• Rationale: If any offspring show the recessive phenotype, the parent was heterozygous;
if all show the dominant phenotype, the parent was likely homozygous dominant.
5. What is Incomplete Dominance?
• Answer: A pattern where the heterozygote displays an intermediate phenotype between
the two homozygotes.
• Rationale: In snapdragons, crossing red (RR) and white (rr) produces pink (Rr) because
neither allele is completely dominant.
6. Define Codominance.
• Answer: A condition where both alleles in a heterozygote are fully expressed.
• Rationale: In AB blood types, both the A and B antigens are present on the red blood cell
surface.
7. Mendel’s Law of Segregation states that:
• Answer: The two alleles for a heritable character separate during gamete formation and
end up in different gametes.
• Rationale: This ensures that each gamete carries only one allele for each gene.
8. What is the phenotypic ratio of a Mendelian dihybrid cross (AaBb x AaBb)?
• Answer: 9:3:3:1.
• Rationale: This represents the distribution of two independent traits following the law of
independent assortment.
9. Define Epistasis.
• Answer: One gene masks or interferes with the expression of another gene.
• Rationale: In coat color of Labradors, one gene determines pigment color, but another
gene determines if that pigment is actually deposited in the hair.
10. What is Pleiotropy?
, • Answer: When a single gene affects multiple, seemingly unrelated phenotypic traits.
• Rationale: Cystic fibrosis is pleiotropic because one gene mutation affects the lungs,
pancreas, and sweat glands.
11. In a pedigree, a filled-in square represents what?
• Answer: An affected male.
• Rationale: Squares represent males, circles represent females, and shading indicates the
presence of the trait/disorder.
12. If a trait skips generations and affects both males and females, it is likely:
• Answer: Autosomal Recessive.
• Rationale: Recessive traits can be carried silently by heterozygotes; autosomal means it
isn't linked to sex chromosomes.
13. What is Polygenic Inheritance?
• Answer: The determination of a particular characteristic by many genes.
• Rationale: Traits like human skin color or height show a continuous gradient because
they are influenced by multiple loci.
14. What is a "Locus"?
• Answer: The specific physical location of a gene on a chromosome.
• Rationale: Each gene occupies a fixed position, which is consistent across members of
the same species.
15. If a woman is a carrier for Hemophilia (X-linked recessive) and marries a normal male,
what is the chance their son will have hemophilia?
• Answer: 50%.
• Rationale: The son receives a Y from the father and either the normal X or the mutant X
from the mother.
16. Define Hemizygous.
• Answer: Having only one copy of a gene in a diploid organism.
• Rationale: Human males are hemizygous for genes on the X chromosome because they
only have one X.
17. What is the "Norm of Reaction"?
