Biology Unit 6 Review

A heterozygous (Bb) dragon is crossed with a homozygous recessive (bb) dragon. Which of the following Punnett squares correctly represents this cross?

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In horses, the allele for straight hair (H) is dominant, and the allele for curly hair (h) is recessive.  A horse breeder mates a homozygous dominant mother with a homozygous recessive father.  What is the genotypic ratio of the offspring?

• 2HH: 0Hh: 2hh

• 0HH: 4Hh: 0hh

• 2HH: 2Hh: 0hh

If brown fur is dominant (A) and yellow fur is recessive (a) in puppies, what is the chance that the offspring of two heterozygous (Aa) parents will have yellow fur?

• 25%

• 50%

• 75%

Two parents are crossed together.  Parent 1 is heterozygous  dominant and Parent 2 is homozygous recessive. What percentage of the offspring can be expected to express the dominant phenotype?  (See image provided)

• 0%

• 50%

• 70%

An organism that has identical or the same alleles for a trait.

• Heterozygous

• Homozygous

• Recessive

An allele that is only expressed when both copies are present (aa).

• Homozygous

• Dominant

• Recessive

An organism that has two different alleles for a trait

• Heterozygous

• Phenotype

• Genotype

Set of alleles (AA, Aa, aa) an individual has.

• Recessive

• Dominant

• Genotype

Describes an allele that is always expressed if present (Aa, AA).

• Recessive

• Dominant

• Heterozygous

The Physical features of an individual

• Phenotype

• Heterozygous

• Homozygous