Question 1

Which of the following best explains why Mendel chose pea plants for his experiments on inheritance?

Accepted Answer

Pea plants have easily identifiable traits and can be easily controlled for pollination.

Question 2

A cross between a true-breeding purple-flowered pea plant (PP) and a true-breeding white-flowered pea plant (pp) produces all purple-flowered offspring in the F1 generation. What does this result demonstrate?

Accepted Answer

The purple allele is dominant over the white allele.

Question 3

If two heterozygous tall pea plants (Tt) are crossed, what is the probability that an offspring will be short? (Assume tall is dominant to short.)

Accepted Answer

$$\frac{1}{4}$$

Question 4

Which of the following statements describes the law of segregation?

Accepted Answer

The two alleles for a heritable character separate during gamete formation.

Question 5

A testcross is performed between a plant with an unknown genotype showing the dominant phenotype and a homozygous recessive plant. If any offspring display the recessive phenotype, what is the genotype of the unknown parent?

Accepted Answer

Heterozygous

Question 6

In a dihybrid cross between two individuals heterozygous for both traits (AaBb x AaBb), what is the expected phenotypic ratio if the genes assort independently?

Accepted Answer

9:3:3:1

Question 7

Which of the following is an example of incomplete dominance?

Accepted Answer

A cross between red and white flowers produces pink flowers.

Question 8

A woman with genotype $$I^A i ($$blood type A) and a man with genotype $$ii ($$blood type O) have children. What are the possible blood types of their offspring?

Accepted Answer

A and O

Question 9

Which of the following best describes pleiotropy?

Accepted Answer

A single gene affects multiple phenotypic traits.

Question 10

A couple, both with genotype Cc for a genetic disorder, have three children. What is the probability that all three children will be unaffected (not cc)?

Accepted Answer

$$\left(\frac{3}{4}\$$right)^3$$

Question 11

Which of the following is an example of a polygenic trait?

Accepted Answer

Human height

Question 12

If the probability of producing an Aa offspring from a cross is $$\frac{1}{2}$$ and the probability of producing a Bb offspring is $$\frac{1}{2}$$, what is the probability of producing an AaBb offspring?

Accepted Answer

$$\frac{1}{4}$$

Question 13

Which of the following best describes codominance?

Accepted Answer

Both alleles contribute to the phenotype in separate, distinguishable ways.

Question 14

Which of the following is a multifactorial disorder?

Accepted Answer

Heart disease

Question 15

A plant with genotype Ww is crossed with a plant with genotype ww. What is the probability that an offspring will have the dominant phenotype?

Accepted Answer

$$\frac{1}{2}$$

Question 16

Which of the following is NOT a reason Mendel’s work was significant to the field of genetics?

Accepted Answer

He discovered DNA as the genetic material.

Question 17

Which of the following crosses would produce a 1:1 phenotypic ratio in the offspring?

Accepted Answer

Heterozygous x homozygous recessive

Question 18

Which of the following best explains why siblings from the same parents can look different from each other?

Accepted Answer

Crossing-over during meiosis creates new combinations of alleles.

Question 19

Which of the following is true about the law of independent assortment?

Accepted Answer

It applies only to genes located on different, nonhomologous chromosomes or far apart on the same chromosome.

Question 20

A genetic disorder is caused by a mutation in a single gene, but the symptoms include effects on the eyes, heart, and skeleton. This is an example of:

Accepted Answer

Pleiotropy

Mendelian Genetics: Principles, Patterns, and Extensions

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