BIOLOGY 100 EXAM 1 EKDALE SDSU
REVIEW 2026 VERIFIED QUESTIONS
WITH COMPLETE ANSWERS
◉ Pea plants were well suited for Mendel's breeding experiments for all
of the following reasons except:
A. Pea plants exhibit variations in a number of observable
characteristics, such as flower color and seed shape.
B. Mendel could control the pollination between different pea plants.
C. It is easy to obtain large numbers of offspring from any given cross.
D. Many of the characteristics that vary in pea plants are not linked
closely on the same chromosome.
E. Pea plants have a particularly long generation time.
Answer: E. Pea plants have a particularly long generation time.
◉ The law of segregation states that:
Answer: the two alleles for a given trait segregate into different gametes.
◉ In pea plants, purple flower color is dominant to white flower color. If
two pea plants that are true breeding for purple flowers are crossed, in
the offspring:
Answer: all of the flowers will be purple.
◉ A test-cross:
,A. Makes it possible to determine the genotype of an individual of
unknown genotype that exhibits the dominant version of a trait.
B. Is a cross between an individual whose genotype for a trait is not
known and an individual is homozygous recessive for the trait
C. Sometimes requires the production of multiple offspring to reveal the
genotype of an individual whose genotype is unknown (but who exhibits
the dominant phenotype).
D. Only A. and B. are correct.
E. Choices A., B., and C. are correct.
Answer: E. Choices A., B., and C. are correct.
◉ All of the offspring of a black hen and a white rooster are gray. The
simplest explanation for this pattern of inheritance is:
Answer: incomplete dominance.
◉ A woman with type B blood and a man with type A blood could have
children with which of the following phenotypes?
A. AB only
B. AB or O only
C. A, B, or O only
D. A or B only
E. A, B, AB, or O
Answer: E. A, B, AB, or O
, ◉ A rare X-linked dominant condition in humans, congenital
generalized hypertrichosis (CGH), is marked by excessive hair growth
all over a person's bod. Which of the following statements about this
condition is incorrect?
A. The son of a woman with CGH has just slightly more than a 50%
chance of having this disease.
B. All daughters of a man with CGH will have this disease.
C. The daughter of a woman with CGH has just slightly more than a
50% chance of having this disease.
D. Every son of a woman with CGH will have this disease.
E. The son of a man with CGH is no more likely to have this condition
than the son of a man who doesn't have CGH.
Answer: D. Every son of a woman with CGH will have this disorder.
◉ Individuals carrying two nonfunctioning alleles for the gene
producing the enzyme that converts phenylalanine into tyrosine:
Answer: may or may not develop PKU symptoms, because diet also
plays a role in determining their phenotype.
◉ Thousands (or even tens of thousands) of different traits make up an
individual. For this reason:
Answer: in a species with 23 different chromosomes, some traits must
be coded for by genes on the same chromosome.
◉ In a set of classic experiments performed in the early 1950s, Urey and
Miller subjected an experimental system composed of H2, CH4
REVIEW 2026 VERIFIED QUESTIONS
WITH COMPLETE ANSWERS
◉ Pea plants were well suited for Mendel's breeding experiments for all
of the following reasons except:
A. Pea plants exhibit variations in a number of observable
characteristics, such as flower color and seed shape.
B. Mendel could control the pollination between different pea plants.
C. It is easy to obtain large numbers of offspring from any given cross.
D. Many of the characteristics that vary in pea plants are not linked
closely on the same chromosome.
E. Pea plants have a particularly long generation time.
Answer: E. Pea plants have a particularly long generation time.
◉ The law of segregation states that:
Answer: the two alleles for a given trait segregate into different gametes.
◉ In pea plants, purple flower color is dominant to white flower color. If
two pea plants that are true breeding for purple flowers are crossed, in
the offspring:
Answer: all of the flowers will be purple.
◉ A test-cross:
,A. Makes it possible to determine the genotype of an individual of
unknown genotype that exhibits the dominant version of a trait.
B. Is a cross between an individual whose genotype for a trait is not
known and an individual is homozygous recessive for the trait
C. Sometimes requires the production of multiple offspring to reveal the
genotype of an individual whose genotype is unknown (but who exhibits
the dominant phenotype).
D. Only A. and B. are correct.
E. Choices A., B., and C. are correct.
Answer: E. Choices A., B., and C. are correct.
◉ All of the offspring of a black hen and a white rooster are gray. The
simplest explanation for this pattern of inheritance is:
Answer: incomplete dominance.
◉ A woman with type B blood and a man with type A blood could have
children with which of the following phenotypes?
A. AB only
B. AB or O only
C. A, B, or O only
D. A or B only
E. A, B, AB, or O
Answer: E. A, B, AB, or O
, ◉ A rare X-linked dominant condition in humans, congenital
generalized hypertrichosis (CGH), is marked by excessive hair growth
all over a person's bod. Which of the following statements about this
condition is incorrect?
A. The son of a woman with CGH has just slightly more than a 50%
chance of having this disease.
B. All daughters of a man with CGH will have this disease.
C. The daughter of a woman with CGH has just slightly more than a
50% chance of having this disease.
D. Every son of a woman with CGH will have this disease.
E. The son of a man with CGH is no more likely to have this condition
than the son of a man who doesn't have CGH.
Answer: D. Every son of a woman with CGH will have this disorder.
◉ Individuals carrying two nonfunctioning alleles for the gene
producing the enzyme that converts phenylalanine into tyrosine:
Answer: may or may not develop PKU symptoms, because diet also
plays a role in determining their phenotype.
◉ Thousands (or even tens of thousands) of different traits make up an
individual. For this reason:
Answer: in a species with 23 different chromosomes, some traits must
be coded for by genes on the same chromosome.
◉ In a set of classic experiments performed in the early 1950s, Urey and
Miller subjected an experimental system composed of H2, CH4
