UNIT 5: concept 1 quiz (plus punnett squares)

Which form of a gene is expressed in the phenotype even if only one copy is present?

• A. recessive

• B. dominant

• C. homologous

• D. heterozygous

In a genetic cross between two heterozygous tall pea plants, where tall is dominant over short, what is the expected phenotypic ratio of the offspring?

• A. 100% tall.

• B. 75% tall, 25% short.

• C. 50% tall, 50% short.

• D. 25% tall, 75% short.

Which principle explains why an organism with the genotype ‘Aa’ will exhibit the dominant trait?

• A. Law of Dominance

• B. Law of Segregation

• C. Law of Independent Assortment

• D. Chromosome Theory of Inheritance

What is the genotype of an organism with one dominant and one recessive allele for a trait?

• A. diploid

• B. homozygous recessive

• C. heterozygous

• D. homozygous dominant

Two parents are carriers of a genetic disorder caused by a recessive allele, with genotypes Gg. What is the probability that their child will be a carrier of the disorder?

• A. 25%

• B. 50%

• C. 75%

• D. 100%

Which Mendelian law of inheritance states that organisms inherit two copies of each gene and donate one copy to each of their offspring?

• A. Law of Dominance

• B. Law of Segregation

• C. Law of Independent Assortment

• D. Chromosome Theory of Inheritance

In cats, the allele for a thick, long coat (L) is dominant to the allele for a soft, short coat (l). A long coat cat and a short coat cat mate. They produce several litters, 50% are long coat and 50% are short coat. What must be the genotypes of the parents to create this phenotypic ratio?

• A. LL × ll

• B. Ll × ll

• C. LL × Ll

• D. Ll × Ll

Imagine two heterozygous parents. Each has a dominant allele (B) for brown eyes and a recessive allele (b) for blue eyes. What would the genotypic ratio of the offspring be?

• A. 100% Bb

• B. 50% BB, 50% Bb

• C. 25% BB, 50% Bb, 25% bb

• D. 50% Bb, 50% bb