Question 1

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

Accepted Answer

Alleles for a heritable character separate during gamete formation, so each gamete carries only one allele for each gene.

Question 2

A plant with genotype AaBb is crossed with another plant of genotype AaBb. What is the probability that an offspring will be homozygous recessive for both traits?

Accepted Answer

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

Question 3

Which scenario best illustrates the concept of incomplete dominance?

Accepted Answer

A cross between a red-flowered and a white-flowered plant produces pink-flowered offspring.

Question 4

In a dihybrid cross between two heterozygous individuals (AaBb x AaBb), what is the expected phenotypic ratio in the F2 generation?

Accepted Answer

9:3:3:1

Question 5

Which of the following is an example of codominance?

Accepted Answer

A person with AB blood type expresses both A and B antigens equally.

Question 6

If two carriers of a recessive genetic disorder (Aa x Aa) have a child, what is the probability that the child will be affected by the disorder?

Accepted Answer

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

Question 7

Which statement best explains the Law of Independent Assortment?

Accepted Answer

Alleles of different genes assort independently of one another during gamete formation.

Question 8

A pedigree shows that a trait skips generations and affects both males and females equally. What is the most likely mode of inheritance?

Accepted Answer

Autosomal recessive

Question 9

If a child inherits one sickle cell allele and one normal allele, what phenotype will they most likely display?

Accepted Answer

They will have sickle cell trait and may show mild symptoms under low oxygen conditions.

Question 10

Which of the following best describes a testcross?

Accepted Answer

Crossing an individual of unknown genotype with a homozygous recessive individual.

Question 11

A woman who is heterozygous for a dominant trait (Aa) and a man who is homozygous recessive (aa) have a child. What is the probability that the child will express the dominant phenotype?

Accepted Answer

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

Question 12

Which of the following is NOT a possible genotype for a person with type A blood?

Accepted Answer

ii

Question 13

If the probability of inheriting allele A from one parent is $$\frac{1}{2}$$ and the probability of inheriting allele B from the other parent is $$\frac{1}{2}$$, what is the probability of inheriting both alleles?

Accepted Answer

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

Question 14

Which of the following genetic disorders is caused by a lethal dominant allele?

Accepted Answer

Huntington's disease

Question 15

A pedigree shows that a trait is present in every generation and affected individuals have at least one affected parent. What is the most likely mode of inheritance?

Accepted Answer

Autosomal dominant

Question 16

Which of the following best explains why a lethal dominant allele can persist in a population?

Accepted Answer

Symptoms appear after reproductive age, allowing carriers to pass on the allele.

Question 17

Which of the following is an example of a real-world application of Mendel's laws in medicine?

Accepted Answer

Predicting the probability of a child inheriting cystic fibrosis from carrier parents.

Question 18

If a genotype is AaBbCcDd x AaBbCcDd, what is the probability that an offspring will be heterozygous for all four traits?

Accepted Answer

$$\left(\frac{1}{2}\$$right)^4$$ = \frac{1}{16}$$

Question 19

Which of the following statements about phenotype and genotype is correct?

Accepted Answer

Phenotype is the observable trait, while genotype is the genetic makeup.

Question 20

Which of the following best describes the relationship between dominant and recessive alleles at the molecular level?

Accepted Answer

Dominant alleles often produce a functional protein, while recessive alleles may produce a nonfunctional protein.

Mendel and the Gene Idea: Principles of Inheritance

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