Q: If two heterozygous individuals (Aa) are crossed, what is the probability that their offspring will be homozygous recessive (aa)? Use the rule of multiplication.

Probability = $$\frac{1}{2} \times \frac{1}{2} = \frac{1}{4}$$

Question 1

Which of the following best describes the Law of Independent Assortment as demonstrated by Mendel's dihybrid cross experiments?

Accepted Answer

Alleles for different traits segregate independently during gamete formation.

Question 2

A true-breeding pea plant with purple flowers (PP) is crossed with a true-breeding white flower plant (pp). What is the expected genotype and phenotype ratio in the F2 generation after self-crossing the F1 hybrids?

Accepted Answer

Genotype ratio: 1 PP : 2 Pp : 1 pp; Phenotype ratio: 3 purple : 1 white

Question 3

If two heterozygous individuals (Aa) are crossed, what is the probability that their offspring will be homozygous recessive (aa)? Use the rule of multiplication.

Accepted Answer

Probability = $$\frac{1}{2} 	imes \frac{1}{2} = \frac{1}{4}$$

Question 4

Which scenario best illustrates codominance?

Accepted Answer

A cow with red hair crossed with a cow with white hair produces offspring with both red and white patches.

Question 5

In a dihybrid cross of RrYy x RrYy, what is the expected phenotypic ratio for the offspring?

Accepted Answer

9:3:3:1

Question 6

Which of the following best describes epistasis?

Accepted Answer

One gene at one locus alters the phenotypic expression of a gene at a second locus.

Question 7

A pedigree chart shows a trait that appears in every generation and affects both males and females equally. What is the most likely mode of inheritance?

Accepted Answer

Autosomal dominant

Question 8

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 9

A man with genotype $$X^R Y$$ and a woman with genotype $$X^R X^r$$ have children. What is the probability that a son will have white eyes (recessive trait)?

Accepted Answer

Probability = $$\frac{1}{2}$$

Question 10

Which of the following is an example of incomplete dominance?

Accepted Answer

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

Question 11

If genes A and B are 17 map units apart, what is the expected recombinant frequency between them?

Accepted Answer

17%

Question 12

Which of the following best describes a genotype?

Accepted Answer

The genetic constitution of an individual

Question 13

A couple, both heterozygous for four genes (AaBbCcDd), have a child. What is the probability that the child will be homozygous recessive for all four genes (aabbccdd)?

Accepted Answer

Probability = $$\left(\frac{1}{4}\$$right)^4$$ = \frac{1}{256}$$

Question 14

Which of the following is NOT a characteristic of sex-linked inheritance?

Accepted Answer

Traits are inherited independently of the sex chromosomes.

Question 15

Which of the following is true about gene linkage?

Accepted Answer

Genes that are close together on the same chromosome are more likely to be inherited together.

Question 16

In the ABO blood group system, how many possible phenotypes can be observed?

Accepted Answer

Four

Question 17

Which term describes an individual with two identical alleles for a gene?

Accepted Answer

Homozygous

Question 18

A family pedigree shows a trait that skips generations and is more common in males. What is the most likely mode of inheritance?

Accepted Answer

X-linked recessive

Question 19

Which of the following best describes a phenotype?

Accepted Answer

The observable traits of an individual

Genes and Chromosomes: Mendelian and Non-Mendelian Genetics

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