Final Exam Review 2021

Which of the following represents an organism that homozygous dominant for a trait?

• Rr

• RR

• rR

• rr

The allele for green pod color (G) is dominant over the allele for yellow pod color (g). What is the genotype for a plant

with yellow pods?

• GG

• gG

• gg

• Gg

An organism with two different alleles for a single trait is ____ for that trait.

• Dominant

• Heterozygous

• Recessive

• Homozygous

In pea plants, tall plants are dominant over short plants. What is the genotypic percentage of offspring resulting from a cross between a heterozygous tall plant and another heterozygous tall plant?

• 25% TT; 50% Tt; 25% tt

• 50% tall; 50% short

• 75% tall; 25% short

• 75% TT, 25% tt

In mice black fur (B) is dominant over white fur (b). What is the phenotypic percentage of offspring from a cross between heterozygous black mouse and a white mouse?

• 75% black; 25% white

• 100% gray

• 100% black; 0% white

• 50% black; 50% white

A cross between two plants that have pink flowers produced offspring that have red, pink, or white flowers. Which is the most likely explanation for these results?

• The allele for flower color mutated.

• The allele for flower color is codominant.

• The allele for flower color shows incomplete dominance.

• Crossing over of red and white alleles occurred during meiosis.

A person with B blood type could have the genotype

• BO

• AO

• AB

• OO

Normal human females develop from fertilized eggs containing which of the following sex chromosome combinations?

• OO

• XO

• XY

• XX

In the Punnett square below, eye color for fruit flies is a sex-linked trait. Red (R) is dominant over white (r).

The expected percentage of female fruit flies that are considered carriers is:

• 0% of females would be carriers.

• 25% of females would be carriers.

• 50% of females would be carriers.

• 100% of females would be carriers.

Which nucleic acid has a double helix structure?

• mRNA

• rRNA

• DNA

• tRNA