Unit Test — Unit test Answers

A cross is performed between a bird that is homozygous for red feathers and a bird that is homozygous for blue feathers. Purple offspring result due to incomplete dominance. Then, two of the purple offspring are crossed. What proportion of the offspring from the second cross will be purple?

In roses, red flowers and long stems are dominant traits. A rose plant that is homozygous for both red flowers and long stems is crossed with a rose plant that is heterozygous for red flowers and homozygous for short stems. What percentage of the offspring will exhibit red, long-stemmed flowers?

Some flowering plants appear to have offspring that have traits that are intermediate between those of the parents. Which type of dominance is exhibited by the offspring?

Red-green color blindness is an X-linked recessive disorder. What is the probability of the offspring having red-green color blindness for the cross that is represented by the Punnett square?

A plant that has round and yellow seeds (RrYy) is crossed with a plant that has round and yellow seeds (RrYy). What is the ratio of the offspring that will have round and yellow seeds?Key: R = round r = wrinkled Y = yellow y = green

Cystic fibrosis is a genetic disorder. It is a recessive trait that is determined by two alleles. Suppose two parents each carry at least one recessive allele, but neither of them has cystic fibrosis. Which statement reflects the likelihood of a child of these parents having cystic fibrosis?

Mendel was able to study seven traits in all the pea plants in each generation. Which of his hypotheses allowed him to analyze each trait separately?

The pedigree traces red-green color blindness. Which family members have red-green color blindness?

Mendel’s pea plants had either purple or white flowers. This means that the plants

If Mendel had crossed a true breeding dominant plant with a true breeding recessive plant, in which of the three generations is the recessive trait visible?

Which scenario breaks the law of segregation?

The Punnett square predicts the ratio of genotypes in the offspring based on the genotypes of the parents. Which Punnett square represents a cross between a mom who is heterozygous for dimples and a dad who is homozygous for no dimples?

The diagram represents a dihybrid cross between two pea plants heterozygous for both seed color and seed shape.What is the phenotypic ratio of the offspring?

Pedigrees help geneticists understand how traits are inherited between generations. Red-green color blindness is a sex-linked disorder that is determined by a recessive allele on the X chromosome.If Brian has a son who is color-blind, what is known about the genotype of the son's mother?

Which are different forms of the same gene?