Genetics

Which describes the type of cross shown in the picture?

• co dominance: both homozygous alleles make up the phenotype for the heterozygous
• incomplete dominance: both homozygous alleles become a mixture for the heterozygous
• Mutation: change in the DNA
• Nondisjunction: chromosomes separate incorrectly

Straight hair is dominant to curly hair.
Which parents will give a 25% chance of having offspring with curly hair?

• 2 heterozygous straight hair (Tt)
• 2 homozygous straight hair (TT)
• 1 homzygous curly (tt) and 1 homzygous straight (TT)
• 1 heterozygous straight (Tt) and 1 homozgyous curly (tt) 

Mrs. Jones has blood type AA.
Mr. Jones has blood type AB.
What are the genotypes of her offspring?

• 100% AB
• 25% AO; 25% BO; 25% AA; 25% AB 
• 50% AA; 50% AB
• 100% AA

Curly hair is dominant to straight hair.
Two straight hair individuals are crossed. What will be the phenotypes of the offspring?

• 100% straight
• 50% straight; 50% curly
• 75% curly; 25% straight
• 100% curly

In a heterozygous genotype, the ___________ allele takes over in the phenotype.

• recessive
• dominant
• lower case letter
• both 

Which of the following is NOT a genotype?

• heterozygous
• a trait
• Bb
• homozygous recessive

Which of the following alleles is homozygous (purebred) recessive?

• Tt
• tt
• TT
• t

Two brown eyed parents (Bb) have a baby. What is the chance the baby is blue eyed?

• 0 %
• 25%
• 50%
• 75%

Heterozygous is when...

• the alleles are the same
• the alleles are different
• the alleles are absent
• the alleles are present

In a pedigree, what shape represents a male?

• circle
• square
• triangle
• diamond