BIOD 210 Genetics Final Exam – Practice Questions &
Rationales
Based on the available search results, I have compiled a comprehensive set of practice
questions covering key topics for the BIOD 210 Genetics Final Exam. These questions are
derived from unofficial student-shared resources and designed to help you prepare
effectively for the 2026/2027 testing cycle .
SECTION 1: MENDELIAN GENETICS & INHERITANCE
PATTERNS
Question 1
In pea plants, tall (T) is dominant over dwarf (t). What is the genotypic ratio of offspring
from a cross between a heterozygous tall plant and a dwarf plant?
A) 1 TT : 2 Tt : 1 tt
B) 3 tall : 1 dwarf
C) 1 Tt : 1 tt
D) All Tt
Correct Answer: C
Rationale: Tt × tt produces 50% Tt (tall) and 50% tt (dwarf). The genotypic ratio is 1:1. This
is a test cross used to determine if a dominant phenotype is homozygous or heterozygous .
Question 2
A woman with type A blood (genotype AO) and a man with type B blood (genotype BO)
have a child. What is the probability the child has type O blood?
A) 0%
B) 25%
, C) 50%
D) 75%
Correct Answer: B
Rationale: AO × BO — possible gametes: A, O from mother; B, O from father. OO (type O)
occurs when both contribute O: 1/2 × 1/2 = 1/4 (25%). The ABO blood group
demonstrates codominance, where both A and B antigens are expressed equally .
Question 3
In a monohybrid cross between two heterozygotes (Aa × Aa), what proportion of the
offspring that show the dominant phenotype are homozygous dominant?
A) 1/4
B) 1/3
C) 1/2
D) 2/3
Correct Answer: B
Rationale: Offspring: 1 AA : 2 Aa : 1 aa. The dominant phenotype includes AA and Aa (3
total). Of these, 1 is AA, so 1/3 of the dominant phenotype offspring are homozygous
dominant .
Question 4
In snapdragons, flower color shows incomplete dominance. Red (RR) × white (WW)
produces pink (RW). What is the phenotypic ratio from RW × RW?
A) 3 red : 1 white
B) 1 red : 2 pink : 1 white
C) 1 red : 1 white
D) All pink
Correct Answer: B
Rationales
Based on the available search results, I have compiled a comprehensive set of practice
questions covering key topics for the BIOD 210 Genetics Final Exam. These questions are
derived from unofficial student-shared resources and designed to help you prepare
effectively for the 2026/2027 testing cycle .
SECTION 1: MENDELIAN GENETICS & INHERITANCE
PATTERNS
Question 1
In pea plants, tall (T) is dominant over dwarf (t). What is the genotypic ratio of offspring
from a cross between a heterozygous tall plant and a dwarf plant?
A) 1 TT : 2 Tt : 1 tt
B) 3 tall : 1 dwarf
C) 1 Tt : 1 tt
D) All Tt
Correct Answer: C
Rationale: Tt × tt produces 50% Tt (tall) and 50% tt (dwarf). The genotypic ratio is 1:1. This
is a test cross used to determine if a dominant phenotype is homozygous or heterozygous .
Question 2
A woman with type A blood (genotype AO) and a man with type B blood (genotype BO)
have a child. What is the probability the child has type O blood?
A) 0%
B) 25%
, C) 50%
D) 75%
Correct Answer: B
Rationale: AO × BO — possible gametes: A, O from mother; B, O from father. OO (type O)
occurs when both contribute O: 1/2 × 1/2 = 1/4 (25%). The ABO blood group
demonstrates codominance, where both A and B antigens are expressed equally .
Question 3
In a monohybrid cross between two heterozygotes (Aa × Aa), what proportion of the
offspring that show the dominant phenotype are homozygous dominant?
A) 1/4
B) 1/3
C) 1/2
D) 2/3
Correct Answer: B
Rationale: Offspring: 1 AA : 2 Aa : 1 aa. The dominant phenotype includes AA and Aa (3
total). Of these, 1 is AA, so 1/3 of the dominant phenotype offspring are homozygous
dominant .
Question 4
In snapdragons, flower color shows incomplete dominance. Red (RR) × white (WW)
produces pink (RW). What is the phenotypic ratio from RW × RW?
A) 3 red : 1 white
B) 1 red : 2 pink : 1 white
C) 1 red : 1 white
D) All pink
Correct Answer: B
