Test Review Ch. 7

Two kittens in a litter are genetically different from each other and from their parents. These genetic differences are most directly due to

• sexual reproduction

• asexual reproduction

• cloning

• evolution

Traits are passed from parents to offspring. These traits are determined by

• chromosomes, located on genes, found in the nucleus

• genes, located on chromosomes, found in the nucleus

• chromosomes, located on genes, found in the ribosomes

• genes, located on chromosomes, found in the ribosomes

Identical twins were separated at birth and raised by two different families. Years later, one twin was a physically fit member of the cross-country team, and the other twin was overweight with slightly higher-than-normal blood pressure. The differences in these twins could be explained by the fact that

• the genes in the two individuals are completely different

• in twins, each individual inherits genes from only one parent

• the DNA bases in twins combine differently

• the environment can influence the expression of genes

The hair colors of the members of a family are listed below.

mother – brown hair

father – blond hair

older son – brown hair

younger son – blond hair

The hair colors of the sons are most likely a direct result of

• natural selection in males

• heredity

• evolution

• environmental influences

A student studying feather color inheritance in a certain species of chickens observes that the chickens have black (homozygous), blue (heterozygous) feathers. The student hypothesizes that this feather color trait follows the incomplete dominance inheritance pattern.

Which data table would support the student's hypothesis?

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The diagram depicts the process of crossing over, which occurs between homologous chromosomes during gamete formation.

What is the result of this process?

• the production of gametes that are genetically identical

• the deletion of amino acids in proteins

• an increase in mutations in genetic material

• an increase in offspring variation

In a particular species of mice, a single gene (B or b) determines tail length. The short-tail allele is sex-linked and dominant. Shading in the pedigree below indicates that an individual has a short tail. The pedigree shows the pattern of inheritance of the short-tail allele over three generations of mice.

Individual 6 is female. What is the genotype of individual 6?

• X^BX^b

• X^bX^b

• X^BY

• X^bY

A scientist is examining a pedigree that includes several generations of an organism with XX/XY chromosome sex determination.

Which pattern of inheritance would support the hypothesis that the trait being studied is a recessive sex-linked trait found on the x chromosome?

• The trait is only expressed in males who have a father with the trait.

• The trait is expressed in half of the female organisms and all of the male organisms.

• The trait is mostly expressed in males who have a maternal grandfather with the trait.

• The trait is mostly expressed in females who have a paternal grandmother with the trait.

Students conduct an experiment to test whether or not the trait for pollen shape and the trait for flower color are next to each other on the same chromosome in pea plants. They cross two plants that are known to be heterozygous for both traits to produce offspring.

Long pollen shape (L) is dominant over round pollen shape (l). Purple flower color (P) is dominant over red flower color (p).

Choose the graph that shows the correct phenotype frequency that would be expected if the traits are linked and the dominant traits are next to each other on the same chromosome for both plants.

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A species of butterfly, Heliconius cydno alithea, has both white and yellow individuals. Its white allele is dominant and its yellow allele is recessive. The graph shows the genotype frequency for a generation of the butterfly.

If a predator introduced to the butterfly habitat prefers the yellow trait, predict the genotype frequencies that will occur in the third generation. Which of the following models the genotype frequency in the new generation, assuming all genotypes are represented?

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