Page 1 of 51
BIOD 210 – GENETICS – 2026 FINAL EXAM
COMPLETE (160) CURRENT TESTING
QUESTIONS AND CORRECT ANSWERS WITH
DETAILED RATIONALES|GRADED A+.
BIOD
Prepare for the BIOD 210 Final Exam – Genetics Portage Learning with
practice questions covering DNA structure and replication,
Mendelian inheritance, gene expression, mutations, chromosomal
abnormalities, and molecular genetics principles. This study guide
helps reinforce essential genetics concepts and supports effective
biology exam preparation. Designed to improve critical thinking skills
and boost confidence in analyzing hereditary and molecular
processes. Suitable for biology, pre-med, nursing, and allied health
students.
MULTIPLE CHOICE.
Section 1: Mendelian Genetics & Inheritance Patterns
(Questions 1–25)
1. A cross between a homozygous dominant (AA) and a homozygous
recessive (aa) produces F₁ offspring that are all Aa. When the F₁ are
self-crossed, the genotypic ratio in the F₂ is:
A) 1:1
B) 3:1
C) 1:2:1
D) 9:3:3:1
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Answer: C. 1:2:1
Explanation: Aa × Aa gives 1 AA : 2 Aa : 1 aa.
2. In a dihybrid cross with independent assortment and complete
dominance, the phenotypic ratio is:
A) 1:1:1:1
B) 3:1
C) 9:3:3:1
D) 1:2:1:2:4:2:1:2:1
Answer: C. 9:3:3:1
Explanation: Two heterozygotes (AaBb × AaBb) produce 9 dominant
for both : 3 dominant A recessive B : 3 recessive A dominant B : 1
recessive for both.
3. A testcross is performed by crossing an individual with an
unknown genotype to a:
A) Homozygous dominant individual
B) Heterozygous individual
C) Homozygous recessive individual
D) Individual with the same unknown genotype
Answer: C. Homozygous recessive individual
Explanation: The testcross reveals the unknown genotype by
observing offspring phenotypes.
4. Incomplete dominance is exemplified by:
A) AB blood type
B) Pink flowers from red and white parents
C) Sickle cell trait (carrier has both normal and sickle hemoglobin)
D) Both B and C
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Answer: D. Both B and C
Explanation: Incomplete dominance produces an intermediate
phenotype; sickle cell trait shows both normal and sickle
hemoglobin.
5. Codominance is seen in:
A) AB blood type
B) Flower color in snapdragons
C) Sickle cell anemia
D) Cystic fibrosis
Answer: A. AB blood type
Explanation: Both A and B antigens are fully expressed on red blood
cells.
6. A woman with blood type A (genotype AO) and a man with blood
type B (genotype BO) have a child. The probability the child has
blood type O is:
A) 0%
B) 25%
C) 50%
D) 75%
Answer: B. 25%
Explanation: AO × BO → AB (25%), AO (25%), BO (25%), OO (25%).
7. A recessive disorder appears in a child whose parents are both
unaffected. The parents must be:
A) Both homozygous dominant
B) Both heterozygous (carriers)
C) One homozygous recessive, one heterozygous
D) Both homozygous recessive
, Page 4 of 51
Answer: B. Both heterozygous (carriers)
Explanation: Carriers (Aa) are unaffected but can pass the
recessive allele to an affected child (aa).
8. The probability that two heterozygous carriers (Aa) will have an
affected child (aa) is:
A) 0%
B) 25%
C) 50%
D) 75%
Answer: B. 25%
Explanation: Each child has a 1/4 chance of inheriting both
recessive alleles.
9. In X-linked recessive inheritance, an affected male:
A) Passes the trait to all his daughters
B) Passes the trait to all his sons
C) Never passes the trait to his daughters
D) Passes the trait to half his sons
Answer: A. Passes the trait to all his daughters
Explanation: A male gives his only X to all daughters, so they are
carriers (if mother is normal) or affected (if mother carries the
mutation).
10. A man with hemophilia (X^hY) and a woman who is a carrier
(X^H X^h) have a daughter. The probability that the daughter has
hemophilia is:
A) 0%
B) 25%
BIOD 210 – GENETICS – 2026 FINAL EXAM
COMPLETE (160) CURRENT TESTING
QUESTIONS AND CORRECT ANSWERS WITH
DETAILED RATIONALES|GRADED A+.
BIOD
Prepare for the BIOD 210 Final Exam – Genetics Portage Learning with
practice questions covering DNA structure and replication,
Mendelian inheritance, gene expression, mutations, chromosomal
abnormalities, and molecular genetics principles. This study guide
helps reinforce essential genetics concepts and supports effective
biology exam preparation. Designed to improve critical thinking skills
and boost confidence in analyzing hereditary and molecular
processes. Suitable for biology, pre-med, nursing, and allied health
students.
MULTIPLE CHOICE.
Section 1: Mendelian Genetics & Inheritance Patterns
(Questions 1–25)
1. A cross between a homozygous dominant (AA) and a homozygous
recessive (aa) produces F₁ offspring that are all Aa. When the F₁ are
self-crossed, the genotypic ratio in the F₂ is:
A) 1:1
B) 3:1
C) 1:2:1
D) 9:3:3:1
, Page 2 of 51
Answer: C. 1:2:1
Explanation: Aa × Aa gives 1 AA : 2 Aa : 1 aa.
2. In a dihybrid cross with independent assortment and complete
dominance, the phenotypic ratio is:
A) 1:1:1:1
B) 3:1
C) 9:3:3:1
D) 1:2:1:2:4:2:1:2:1
Answer: C. 9:3:3:1
Explanation: Two heterozygotes (AaBb × AaBb) produce 9 dominant
for both : 3 dominant A recessive B : 3 recessive A dominant B : 1
recessive for both.
3. A testcross is performed by crossing an individual with an
unknown genotype to a:
A) Homozygous dominant individual
B) Heterozygous individual
C) Homozygous recessive individual
D) Individual with the same unknown genotype
Answer: C. Homozygous recessive individual
Explanation: The testcross reveals the unknown genotype by
observing offspring phenotypes.
4. Incomplete dominance is exemplified by:
A) AB blood type
B) Pink flowers from red and white parents
C) Sickle cell trait (carrier has both normal and sickle hemoglobin)
D) Both B and C
, Page 3 of 51
Answer: D. Both B and C
Explanation: Incomplete dominance produces an intermediate
phenotype; sickle cell trait shows both normal and sickle
hemoglobin.
5. Codominance is seen in:
A) AB blood type
B) Flower color in snapdragons
C) Sickle cell anemia
D) Cystic fibrosis
Answer: A. AB blood type
Explanation: Both A and B antigens are fully expressed on red blood
cells.
6. A woman with blood type A (genotype AO) and a man with blood
type B (genotype BO) have a child. The probability the child has
blood type O is:
A) 0%
B) 25%
C) 50%
D) 75%
Answer: B. 25%
Explanation: AO × BO → AB (25%), AO (25%), BO (25%), OO (25%).
7. A recessive disorder appears in a child whose parents are both
unaffected. The parents must be:
A) Both homozygous dominant
B) Both heterozygous (carriers)
C) One homozygous recessive, one heterozygous
D) Both homozygous recessive
, Page 4 of 51
Answer: B. Both heterozygous (carriers)
Explanation: Carriers (Aa) are unaffected but can pass the
recessive allele to an affected child (aa).
8. The probability that two heterozygous carriers (Aa) will have an
affected child (aa) is:
A) 0%
B) 25%
C) 50%
D) 75%
Answer: B. 25%
Explanation: Each child has a 1/4 chance of inheriting both
recessive alleles.
9. In X-linked recessive inheritance, an affected male:
A) Passes the trait to all his daughters
B) Passes the trait to all his sons
C) Never passes the trait to his daughters
D) Passes the trait to half his sons
Answer: A. Passes the trait to all his daughters
Explanation: A male gives his only X to all daughters, so they are
carriers (if mother is normal) or affected (if mother carries the
mutation).
10. A man with hemophilia (X^hY) and a woman who is a carrier
(X^H X^h) have a daughter. The probability that the daughter has
hemophilia is:
A) 0%
B) 25%
