ASU BIO 340 FINAL EXAM QUESTIONS WITH
COMPLETE ANSWERS (2025/2026
LATEST)
You cross two pea plants, both of which have purple flowers.
You are surprised to see that in the first generation, there are
plants with both purple flowers and white flowers. What is the
most likely reason for this?
A. One parent was homozygous recessive and one was
heterozygous
B. A new mutation occurred
C. One parent was homozygous recessive and one was
homozygous dominant
D. Both parental plants were heterozygous
E. One parent was homozygous dominant and one was
heterozygous - ANSWER - >D. Both parental plants were
heterozygous
Monohybrid crosses illustrate what important law suggested by
Mendel?
A. Law of Independent Assortment
B. Law of Segregation
C. Law and Order
D. Law of Heterozygosity
,E. None of the above - ANSWER - >B. Law of Segregation
In a dihybrid cross (yellow, round x yellow, round), what
proportion of the F2 offspring have recessive (wrinkled) seed
shape?
A. 1/8
B. 3/16
C. 1/4
D. 3/4
E. 9/16 - ANSWER - >C. 1/4
In a dihybrid cross (yellow, round x yellow, round), what
proportion of the green F2 offspring are round?
A. 1/8
B. 3/16
C. 1/4
D. 3/4
E. 9/16 - ANSWER - >D. 3/4
In a dihybrid cross (yellow, round x yellow, round), what
proportion of the F2 offspring will be both heterozygous for the
color gene and homozygous dominant for the shape gene?
,A. 1/8
B. 3/16
C. 1/4
D. 3/4
E. 9/16 - ANSWER - >A. 1/8
In a tetrahybrid cross, a plant of the genotype AaBbCcDd is
crossed to itself. What is the probability of obtaining the
phenotype "AbcD" in the offspring?
A. 1/8
B. 1/32
C. 9/256
D. 3/64
E. 1/64 - ANSWER - >C. 9/256
In a tetrahybrid cross, a plant of the genotype AaBbCcDd is
crossed to itself. What is the probability of obtaining the
genotype AaBbCCDd in the offspring?
A. 1/8
B. 1/32
C. 1/4
D. 3/16
E. 1/64 - ANSWER - >B/ 1/32
, In a tetrahybrid cross, a plant of the genotype AaBbCcDd is
crossed to itself. What is the probability of obtaining the
genotype AABbCcdd in the offspring?
A. 1/8
B. 1/32
C. 1/4
D. 3/16
E. 1/64 - ANSWER - >E. 1/64
How many autosomes do humans have?
A. 22 pairs
B. 16
C. 46
D. 23 pairs
E. Depends on gender - ANSWER - >A. 22 pairs
A geneticist is studying flower-color mutations in petunias. He
finds two recessive mutants that have white flowers, rather
than the wildtype purple. He crosses a homozygote for the first
mutation with a homozygote for the second mutation. All the
offspring have white flowers. Which of the following offspring is
the best way to write the genotype of these offspring?
COMPLETE ANSWERS (2025/2026
LATEST)
You cross two pea plants, both of which have purple flowers.
You are surprised to see that in the first generation, there are
plants with both purple flowers and white flowers. What is the
most likely reason for this?
A. One parent was homozygous recessive and one was
heterozygous
B. A new mutation occurred
C. One parent was homozygous recessive and one was
homozygous dominant
D. Both parental plants were heterozygous
E. One parent was homozygous dominant and one was
heterozygous - ANSWER - >D. Both parental plants were
heterozygous
Monohybrid crosses illustrate what important law suggested by
Mendel?
A. Law of Independent Assortment
B. Law of Segregation
C. Law and Order
D. Law of Heterozygosity
,E. None of the above - ANSWER - >B. Law of Segregation
In a dihybrid cross (yellow, round x yellow, round), what
proportion of the F2 offspring have recessive (wrinkled) seed
shape?
A. 1/8
B. 3/16
C. 1/4
D. 3/4
E. 9/16 - ANSWER - >C. 1/4
In a dihybrid cross (yellow, round x yellow, round), what
proportion of the green F2 offspring are round?
A. 1/8
B. 3/16
C. 1/4
D. 3/4
E. 9/16 - ANSWER - >D. 3/4
In a dihybrid cross (yellow, round x yellow, round), what
proportion of the F2 offspring will be both heterozygous for the
color gene and homozygous dominant for the shape gene?
,A. 1/8
B. 3/16
C. 1/4
D. 3/4
E. 9/16 - ANSWER - >A. 1/8
In a tetrahybrid cross, a plant of the genotype AaBbCcDd is
crossed to itself. What is the probability of obtaining the
phenotype "AbcD" in the offspring?
A. 1/8
B. 1/32
C. 9/256
D. 3/64
E. 1/64 - ANSWER - >C. 9/256
In a tetrahybrid cross, a plant of the genotype AaBbCcDd is
crossed to itself. What is the probability of obtaining the
genotype AaBbCCDd in the offspring?
A. 1/8
B. 1/32
C. 1/4
D. 3/16
E. 1/64 - ANSWER - >B/ 1/32
, In a tetrahybrid cross, a plant of the genotype AaBbCcDd is
crossed to itself. What is the probability of obtaining the
genotype AABbCcdd in the offspring?
A. 1/8
B. 1/32
C. 1/4
D. 3/16
E. 1/64 - ANSWER - >E. 1/64
How many autosomes do humans have?
A. 22 pairs
B. 16
C. 46
D. 23 pairs
E. Depends on gender - ANSWER - >A. 22 pairs
A geneticist is studying flower-color mutations in petunias. He
finds two recessive mutants that have white flowers, rather
than the wildtype purple. He crosses a homozygote for the first
mutation with a homozygote for the second mutation. All the
offspring have white flowers. Which of the following offspring is
the best way to write the genotype of these offspring?
