Question 1

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

Accepted Answer

Each individual has two alleles for each trait, and these alleles separate during gamete formation so that each gamete receives only one allele.

Question 2

A pea plant with genotype $$Pp ($$where $$P is $$purple and $$p is $$white) is self-crossed. What is the expected phenotypic ratio in the offspring?

Accepted Answer

$$3:1 (3 $$purple: 1 white)

Question 3

If a plant with genotype $$PP ($$homozygous dominant) is crossed with a plant with genotype $$pp ($$homozygous recessive), what will be the genotype of all F1 offspring?

Accepted Answer

$$Pp$$

Question 4

Which process during meiosis explains Mendel's Law of Independent Assortment?

Accepted Answer

Random orientation of homologous chromosomes during Metaphase I

Question 5

A test cross is performed between a purple-flowered pea plant of unknown genotype and a white-flowered plant ($$pp). If $$all offspring are purple, what is the genotype of the purple parent?

Accepted Answer

$$PP$$

Question 6

Which of the following best defines an allele?

Accepted Answer

An alternative form of a gene found at the same locus on homologous chromosomes

Question 7

In a dihybrid cross between two $$AaBb$$ individuals (genes on separate chromosomes), what is the probability of producing an offspring with genotype $$aabb$$?

Accepted Answer

$$1/16$$

Question 8

A mutation in the gene for pigmentation results in a nonfunctional enzyme. What is the most likely phenotype if the mutation is recessive and the individual is heterozygous?

Accepted Answer

The individual will have normal pigmentation.

Question 9

Which of the following scenarios demonstrates Mendel's Law of Segregation?

Accepted Answer

A heterozygous plant ($$Pp) $$produces gametes with either $$P or$$ $$p$$ alleles.

Question 10

If two heterozygous parents ($$Aa) $$for a recessive disease have a child, what is the probability that the child will be affected by the disease?

Accepted Answer

$$1/4$$

Question 11

A plant with genotype $$AaBb$$ can produce which of the following gametes, assuming independent assortment?

Accepted Answer

$$AB$$, $$Ab$$, $$aB$$, $$ab$$

Question 12

Which of the following best explains why a single base change in DNA can result in a dramatic change in phenotype?

Accepted Answer

It can alter the mRNA and result in a nonfunctional protein, affecting the trait.

Question 13

In a cross between $$Aa$$ and $$aa$$ individuals, what is the expected genotypic ratio among the offspring?

Accepted Answer

$$1:1$$ ($$Aa:aa)$$

Question 14

Which of the following is a real-world example of Mendelian inheritance?

Accepted Answer

Cystic fibrosis, which is inherited as an autosomal recessive trait

Question 15

If two parents are both carriers ($$Aa) $$for a recessive disorder, what is the probability that their first two children will both be carriers?

Accepted Answer

$$1/16$$

Question 16

A pedigree shows that two unaffected parents have a child with a recessive disorder. What are the most likely genotypes of the parents?

Accepted Answer

Both are heterozygous carriers ($$Aa)$$

Question 17

Which of the following statements about homologous chromosomes is correct?

Accepted Answer

They carry the same genes at the same loci, but may have different alleles.

Question 18

In a dihybrid cross ($$AaBb 	imes AaBb$$), what is the expected phenotypic ratio if both traits show complete dominance?

Accepted Answer

$$9:3:3:1$$

Question 19

Which of the following best describes a phenotype?

Accepted Answer

The observable physical or physiological traits of an organism

Question 20

A purple-flowered pea plant has the genotype $$Pp. If it is $$crossed with a white-flowered plant ($$pp$$), what percentage of the offspring are expected to be white?

Accepted Answer

$$50\%$$

Mendelian Genetics: Principles, Laws, and Applications

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