Question 1

Which of the following best describes Mendel’s Law of Segregation?

Accepted Answer

Each gamete receives only one allele of each gene, as alleles separate during gamete formation.

Question 2

In Mendel’s pea plant experiments, what was the phenotypic ratio observed in the F2 generation when crossing true-breeding purple and white flowered plants?

Accepted Answer

$$3:1$$

Question 3

Which statement about homozygous and heterozygous genotypes is correct?

Accepted Answer

Homozygous individuals have two identical alleles for a gene, while heterozygous individuals have two different alleles.

Question 4

A testcross is used to determine the genotype of an individual with a dominant phenotype. Which cross would reveal if the individual is homozygous or heterozygous?

Accepted Answer

Crossing with a homozygous recessive individual.

Question 5

Which of the following scenarios best illustrates the Law of Independent Assortment?

Accepted Answer

Alleles for flower color and seed shape segregate independently during gamete formation.

Question 6

Which equation represents the probability of obtaining a homozygous recessive offspring from two heterozygous parents ($$Aa 	imes Aa$$)?

Accepted Answer

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

Question 7

Which of the following is an example of incomplete dominance?

Accepted Answer

A red-flowered plant crossed with a white-flowered plant produces pink-flowered offspring.

Question 8

Which genetic phenomenon is illustrated when both alleles in a heterozygote are fully expressed, such as in AB blood type?

Accepted Answer

Codominance

Question 9

A pedigree analysis is most useful for which of the following purposes?

Accepted Answer

Predicting the likelihood of a trait appearing in future generations.

Question 10

Which of the following best describes pleiotropy?

Accepted Answer

One gene affects multiple traits.

Question 11

Which of the following disorders is caused by a recessive allele and results in abnormal hemoglobin that can protect against malaria in heterozygotes?

Accepted Answer

Sickle-cell disease

Question 12

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

Accepted Answer

Hydrangea flower color influenced by soil pH

Question 13

If a trait is determined by the additive effect of two or more genes, what type of inheritance is this?

Accepted Answer

Polygenic inheritance

Question 14

Which of the following best explains why dominant alleles that cause lethal diseases are rare in populations?

Accepted Answer

Affected individuals often die before they can reproduce.

Question 15

Which of the following is true about carriers of recessively inherited disorders?

Accepted Answer

Carriers are heterozygous and phenotypically normal.

Question 16

In a dihybrid cross ($$AaBb 	imes AaBb$$), what is the expected phenotypic ratio if the genes assort independently?

Accepted Answer

$$9:3:3:1$$

Question 17

Which of the following is an example of epistasis?

Accepted Answer

A gene for pigment color is masked by a gene that prevents pigment deposition in hair.

Question 18

Which of the following best describes the difference between pleiotropy and polygenic inheritance?

Accepted Answer

Pleiotropy is when one gene affects many traits, polygenic inheritance is when many genes affect one trait.

Question 19

Which of the following is a real-world example of a recessively inherited disorder?

Accepted Answer

Cystic fibrosis

Mendel and the Gene Idea: Foundations of Inheritance

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