Question 1

Which of the following best describes Mendel's 'particulate' hypothesis of inheritance?

Accepted Answer

Parents pass on discrete heritable units that retain their identity in offspring.

Question 2

In Mendel's experiments with pea plants, what was the phenotypic ratio observed in the F2 generation when crossing two heterozygous plants for a single trait?

Accepted Answer

$$3:1$$

Question 3

A plant with genotype $$Pp ($$purple flowers) is crossed with a plant with genotype $$pp ($$white flowers). What is the expected phenotypic ratio of the offspring?

Accepted Answer

$$1$$ purple : $$1$$ white

Question 4

Which of the following statements about alleles is correct?

Accepted Answer

Alleles are different forms of a gene found at the same locus on homologous chromosomes.

Question 5

What is the probability that two heterozygous parents ($$Aa) $$will have a child who is homozygous recessive ($$aa) $$for a trait?

Accepted Answer

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

Question 6

Which law states that each pair of alleles segregates independently of other pairs during gamete formation?

Accepted Answer

Law of Independent Assortment

Question 7

A couple are both carriers for cystic fibrosis (genotype $$Ff). $$What is the probability that their child will have cystic fibrosis?

Accepted Answer

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

Question 8

Which of the following is an example of incomplete dominance?

Accepted Answer

A red flower crossed with a white flower produces pink flowers.

Question 9

In a dihybrid cross between two $$YyRr$$ pea plants, what is the probability of obtaining an offspring with genotype $$YYRR$$?

Accepted Answer

$$\frac{1}{16}$$

Question 10

Which of the following best explains why polydactyly (extra fingers or toes) is rare in the population, even though it is caused by a dominant allele?

Accepted Answer

The frequency of an allele in a population is not determined by whether it is dominant or recessive.

Question 11

A woman with blood type $$IAIB$$ and a man with blood type $$ii$$ have children. Which blood types are possible for their children?

Accepted Answer

A and B only

Question 12

Which genetic phenomenon describes a single gene affecting multiple phenotypic traits, as seen in sickle-cell disease?

Accepted Answer

Pleiotropy

Question 13

In Labrador retrievers, coat color is determined by two genes. If a black lab ($$BbEe) is $$crossed with another black lab ($$BbEe$$), what is the expected phenotypic ratio of black : chocolate : yellow offspring?

Accepted Answer

$$9:3:4$$

Question 14

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

Accepted Answer

Height, influenced by both genes and nutrition

Question 15

A genetic counselor calculates the probability that a couple, each with a 2/3 chance of being a carrier for a recessive disease, will have a child with the disease. What is the probability?

Accepted Answer

$$\frac{1}{9}$$

Question 16

Which of the following best describes the law of segregation?

Accepted Answer

Two alleles for a heritable character separate during gamete formation.

Question 17

A testcross is performed to determine the genotype of a pea plant with purple flowers. If some offspring have white flowers, what is the genotype of the parent plant?

Accepted Answer

Heterozygous

Question 18

Which of the following is true about polygenic inheritance?

Accepted Answer

It results in quantitative variation, such as human skin color.

Question 19

Which of the following best explains why consanguineous matings increase the risk of recessive genetic disorders?

Accepted Answer

They increase the chance that both parents carry the same rare allele.

Question 20

Which of the following genetic tests is performed by removing a sample of the placenta for analysis?

Accepted Answer

Chorionic villus sampling (CVS)

Mendelian Genetics: Principles and Patterns of Inheritance

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