Unit 8 Review: Punnett And Pedigrees

Front

What is a Punnett square?

Back

A Punnett square is a diagram used to predict the genetic makeup of offspring from a cross between two parents. It shows all possible combinations of alleles.

Front

What does it mean for a plant to be heterozygous?

Back

A heterozygous plant has two different alleles for a trait, such as Tt for height, where 'T' is dominant and 't' is recessive.

Front

What is the expected phenotype ratio of offspring from a cross between a heterozygous tall plant (Tt) and a homozygous short plant (tt)?

Back

50% tall (Tt) and 50% short (tt).

Front

Define incomplete dominance.

Back

Incomplete dominance is a genetic situation in which one allele does not completely dominate another allele, resulting in a phenotype that is a blend of the two.

Front

What is the expected phenotype of a heterozygous individual in incomplete dominance?

Back

A blend of both traits is expressed.

Front

What does a filled square represent in a pedigree chart?

Back

A filled square represents an affected male.

Front

What is the expected phenotypic ratio of offspring from a cross between two heterozygous long-tailed animals (Ll)?

Back

75% long tails (LL or Ll) and 25% short tails (ll).

Front

What is the dominant allele for black hair color in mice?

Back

The allele for black hair color is dominant (B) over the allele for white hair color (b).

Front

What is the phenotypic ratio for the offspring of a heterozygous black mouse (Bb) and a white mouse (bb)?

Back

2 Black (Bb): 2 White (bb) or 1 Black: 1 White.

Front

What does it mean for an allele to be recessive?

Back

A recessive allele is one that is masked by the presence of a dominant allele and only expresses its trait when two copies are present.