Page 1 of 54
BIOD 210 – GENETICS – MODULE 7 2026
EXAM COMPLETE (160) CURRENT TESTING
QUESTIONS AND CORRECT ANSWERS WITH
DETAILED RATIONALES|GRADED A+.
BIOD
Prepare for the BIOD 210 Module 7 Exam – Genetics Portage Learning with
practice questions covering Mendelian genetics, molecular genetics,
gene expression, mutations, chromosome structure, and inheritance
patterns. This study guide helps reinforce essential genetics knowledge
and supports effective biology exam preparation. Designed to improve
scientific understanding and boost confidence in analyzing genetic
principles and hereditary processes. Suitable for biology, pre-med,
nursing, and allied health students.
MULTIPLE CHOICE.
Section 1: Mendelian Genetics & Inheritance Patterns
(Questions 1–30)
1. A cross between two heterozygous individuals (Aa × Aa) for a
single gene with complete dominance is expected to yield what
phenotypic ratio in the offspring?
A) 1:1
B) 3:1
C) 1:2:1
D) 9:3:3:1
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Answer: B. 3:1
Explanation: For a monohybrid cross with complete dominance,
the genotypic ratio is 1:2:1, but the phenotypic ratio is 3 dominant : 1
recessive.
2. In a dihybrid cross between two double heterozygotes (AaBb ×
AaBb) with independent assortment and complete dominance, the
expected phenotypic ratio is:
A) 1:1:1:1
B) 3:1
C) 9:3:3:1
D) 1:2:1
Answer: C. 9:3:3:1
Explanation: The classic Mendelian dihybrid ratio results from
independent assortment of two genes.
3. A testcross is performed between an individual with an unknown
genotype and 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: A testcross uses a homozygous recessive to reveal the
unknown genotype from the offspring phenotypes.
4. Incomplete dominance is characterized by:
A) One allele completely masks the other
B) The heterozygote displays an intermediate phenotype
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C) Both alleles are expressed equally
D) The phenotype depends on the sex of the parent
Answer: B. The heterozygote displays an intermediate phenotype
Explanation: In incomplete dominance (e.g., snapdragon flower
color), the heterozygote is a blend of the two homozygotes.
5. A woman with blood type A (genotype AO) and a man with blood
type B (genotype BO) have a child. What is the probability the child
has blood type O?
A) 0%
B) 25%
C) 50%
D) 75%
Answer: B. 25%
Explanation: AO × BO → possible offspring: AB, AO, BO, OO. OO
occurs with probability 1/4 or 25%.
6. Which of the following is an example of codominance?
A) Pink flowers from red and white parents
B) AB blood type in humans
C) Yellow and green pea seed color
D) Polydactyly
Answer: B. AB blood type in humans
Explanation: In codominance, both alleles are expressed fully; AB
blood type has both A and B antigens.
7. A trait that is controlled by more than one gene is called:
A) Pleiotropic
B) Polygenic
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C) Epistatic
D) Multiple allelic
Answer: B. Polygenic
Explanation: Polygenic traits (e.g., skin color, height) are influenced
by multiple genes.
8. Epistasis occurs when:
A) One gene masks the expression of another gene
B) A single gene affects multiple traits
C) Alleles are equally expressed
D) The environment influences phenotype
Answer: A. One gene masks the expression of another gene
Explanation: Epistasis is an interaction where one gene (epistatic)
hides the effect of another (hypostatic).
9. A man with hemophilia (X-linked recessive) and a woman who is a
carrier have a daughter. What is the probability that the daughter
has hemophilia?
A) 0%
B) 25%
C) 50%
D) 100%
Answer: C. 50%
Explanation: Father X^hY, mother X^H X^h. Daughters: X^H X^h
(carrier) or X^h X^h (affected). Probability 50%.
10. In X-linked recessive inheritance, affected males:
A) Always have affected fathers
B) Inherit the mutation from their mother
BIOD 210 – GENETICS – MODULE 7 2026
EXAM COMPLETE (160) CURRENT TESTING
QUESTIONS AND CORRECT ANSWERS WITH
DETAILED RATIONALES|GRADED A+.
BIOD
Prepare for the BIOD 210 Module 7 Exam – Genetics Portage Learning with
practice questions covering Mendelian genetics, molecular genetics,
gene expression, mutations, chromosome structure, and inheritance
patterns. This study guide helps reinforce essential genetics knowledge
and supports effective biology exam preparation. Designed to improve
scientific understanding and boost confidence in analyzing genetic
principles and hereditary processes. Suitable for biology, pre-med,
nursing, and allied health students.
MULTIPLE CHOICE.
Section 1: Mendelian Genetics & Inheritance Patterns
(Questions 1–30)
1. A cross between two heterozygous individuals (Aa × Aa) for a
single gene with complete dominance is expected to yield what
phenotypic ratio in the offspring?
A) 1:1
B) 3:1
C) 1:2:1
D) 9:3:3:1
, Page 2 of 54
Answer: B. 3:1
Explanation: For a monohybrid cross with complete dominance,
the genotypic ratio is 1:2:1, but the phenotypic ratio is 3 dominant : 1
recessive.
2. In a dihybrid cross between two double heterozygotes (AaBb ×
AaBb) with independent assortment and complete dominance, the
expected phenotypic ratio is:
A) 1:1:1:1
B) 3:1
C) 9:3:3:1
D) 1:2:1
Answer: C. 9:3:3:1
Explanation: The classic Mendelian dihybrid ratio results from
independent assortment of two genes.
3. A testcross is performed between an individual with an unknown
genotype and 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: A testcross uses a homozygous recessive to reveal the
unknown genotype from the offspring phenotypes.
4. Incomplete dominance is characterized by:
A) One allele completely masks the other
B) The heterozygote displays an intermediate phenotype
, Page 3 of 54
C) Both alleles are expressed equally
D) The phenotype depends on the sex of the parent
Answer: B. The heterozygote displays an intermediate phenotype
Explanation: In incomplete dominance (e.g., snapdragon flower
color), the heterozygote is a blend of the two homozygotes.
5. A woman with blood type A (genotype AO) and a man with blood
type B (genotype BO) have a child. What is the probability the child
has blood type O?
A) 0%
B) 25%
C) 50%
D) 75%
Answer: B. 25%
Explanation: AO × BO → possible offspring: AB, AO, BO, OO. OO
occurs with probability 1/4 or 25%.
6. Which of the following is an example of codominance?
A) Pink flowers from red and white parents
B) AB blood type in humans
C) Yellow and green pea seed color
D) Polydactyly
Answer: B. AB blood type in humans
Explanation: In codominance, both alleles are expressed fully; AB
blood type has both A and B antigens.
7. A trait that is controlled by more than one gene is called:
A) Pleiotropic
B) Polygenic
, Page 4 of 54
C) Epistatic
D) Multiple allelic
Answer: B. Polygenic
Explanation: Polygenic traits (e.g., skin color, height) are influenced
by multiple genes.
8. Epistasis occurs when:
A) One gene masks the expression of another gene
B) A single gene affects multiple traits
C) Alleles are equally expressed
D) The environment influences phenotype
Answer: A. One gene masks the expression of another gene
Explanation: Epistasis is an interaction where one gene (epistatic)
hides the effect of another (hypostatic).
9. A man with hemophilia (X-linked recessive) and a woman who is a
carrier have a daughter. What is the probability that the daughter
has hemophilia?
A) 0%
B) 25%
C) 50%
D) 100%
Answer: C. 50%
Explanation: Father X^hY, mother X^H X^h. Daughters: X^H X^h
(carrier) or X^h X^h (affected). Probability 50%.
10. In X-linked recessive inheritance, affected males:
A) Always have affected fathers
B) Inherit the mutation from their mother
