Question 1

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

Accepted Answer

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

Question 2

A true-breeding plant with yellow seeds (YY) is crossed with a true-breeding plant with green seeds (yy). What is the expected genotype ratio in the F2 generation after self-pollinating the F1 hybrids?

Accepted Answer

$$1\ YY : 2\ Yy : 1\ yy$$

Question 3

Which scenario best illustrates the concept of incomplete dominance?

Accepted Answer

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

Question 4

In a dihybrid cross between two individuals heterozygous for both traits (RrYy x RrYy), what is the expected phenotypic ratio in the F2 generation, assuming independent assortment?

Accepted Answer

$$9:3:3:1$$

Question 5

A woman who is a carrier for red-green colorblindness (an X-linked recessive trait) has children with a man who has normal vision. What is the probability that their son will be colorblind?

Accepted Answer

$$50\%$$

Question 6

Which of the following best explains why males are more likely to express X-linked recessive disorders than females?

Accepted Answer

Males have only one X chromosome, so a single recessive allele will result in the disorder.

Question 7

Which inheritance pattern is demonstrated by human blood type AB, where both A and B alleles are fully expressed?

Accepted Answer

Codominance

Question 8

A genetic disorder is caused by a single gene that affects multiple traits, such as sickle cell anemia affecting both red blood cell shape and resistance to malaria. This is an example of:

Accepted Answer

Pleiotropy

Question 9

If a man with blood type A (genotype $$I^A I^O) $$and a woman with blood type B (genotype $$I^B I^O) $$have a child, which blood type is NOT possible for their offspring?

Accepted Answer

None of the above; all are possible

Question 10

Which of the following best describes polygenic inheritance?

Accepted Answer

A single trait is controlled by two or more genes, resulting in a continuous range of phenotypes.

Question 11

A testcross is performed between an individual with an unknown genotype and a homozygous recessive individual. If all offspring display the dominant phenotype, what is the genotype of the unknown parent?

Accepted Answer

Homozygous dominant

Question 12

Which of the following is an example of a sex-linked trait in humans?

Accepted Answer

Hemophilia

Question 13

A woman with normal vision and a man who is colorblind have a daughter who is colorblind. What must be true about the woman's genotype?

Accepted Answer

She is a carrier for colorblindness.

Question 14

Which of the following best explains Mendel's Law of Independent Assortment?

Accepted Answer

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

Question 15

In a cross between two roan cows (codominant for red and white hair), what is the expected phenotypic ratio of their offspring?

Accepted Answer

$$1\ red : 2\ roan : 1\ white$$

Question 16

A mutation occurs in a gene that codes for a protein involved in skin pigmentation. Which of the following best describes this mutation?

Accepted Answer

A permanent change in the genetic material that may alter the trait.

Question 17

Which of the following is a real-world example of pleiotropy?

Accepted Answer

Sickle cell anemia causing both anemia and resistance to malaria.

Question 18

If a trait is controlled by multiple alleles, such as the ABO blood group, how many different genotypes are possible for this trait?

Accepted Answer

Six

Question 19

Which of the following best describes the relationship between genotype and phenotype?

Accepted Answer

Genotype determines phenotype, but environmental factors can also influence phenotype.

Question 20

A pedigree 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

Patterns of Inheritance: Mendelian and Non-Mendelian Genetics

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