Concept Check Questions 15.1 Which of Mendel’s laws relates to the inheritance of alleles for a...

Concept Check Questions

15.1

Which of Mendel’s laws relates to the inheritance of alleles for a single character? Which law relates to the inheritance of alleles for two characters in a dihybrid cross? What is the physical basis of these laws?


15.1

If the eye-color locus in Drosophila were located on an autosome, what would be the sex and phenotype of all the F2 offspring produced by the crosses in Figure 15.4 (orange book) or Figure 15.3 (green book)?


15.2

When two genes are located on the same chromosome, what is the physical basis for the production of recombinant offspring in a test cross between a dihybrid parent and a double-mutant parent?


15.2

For each type of offspring in Figure 15.5 (orange book) or Figure 15.4 (green book), explain the relationship between its phenotype and the alleles contributed by the female parent.


15.2

Genes A, B, and C are located on the same chromosome. Test crosses show that the recombinant frequency between A and B is 28% and between A and C is 12%. Can you determine the linear order of these genes?


15.3

A white-eyed female Drosophila is mated with a red-eyed (wild type) male, the reciprocal cross of that shown in Figure 15.4 (orange book) or Figure 15.3 (green book). What phenotypes and genotypes do you predict for their offspring?


15.3

Neither Tim nor Rhoda has Duchenne muscular dystrophy, but their firstborn son does have it. What is the probability that a second child of this couple will have the disease?


15.4

More common than completely polyploid animals are mosaic polyploids, animals that are diploid except for patches of polyploid cells. How might a mosaic tetraploid—an animal with some cells containing four sets of chromosomes—arise?


15.4

About 5% of individuals with Down syndrome have a chromosomal translocation in which one copy of chromosome 21 is attached to chromosome 14. How could this translocation in a parent’s gonad lead to Down syndrome in a child?


15.4

Explain how a male cat could have the tortoise shell phenotype.


15.5

Gene dosage, the number of active copies of a gene, is important to proper development. Identify and describe two processes that help establish the proper dosage of certain genes.


15.5Reciprocal crosses between two primrose varieties, A and B, produce the following results: A female x B male → offspring with all green (nonvariegated) leaves. B female x A male → offspring with spotted (variegated) leaves. Explain these results.


15.5

Mitochondrial genes are critical to the energy metabolism of cells, but mitochondrial disorders caused by mutations in these genes are usually not lethal. Why not?


16.1

How did bacterial transformation occur in Griffith’s famous experiment?


16.1

In Hershey and Chase’s experiment with the virus T2, what result would you expect if protein were the genetic material?


16.1

A fly has the following percentages of nucleotides in its DNA: 27.3% A, 27.6% T, 22.5% G, 22.5% C. How do these numbers demonstrate Chargaff’s rules?


16.1

How did Watson and Crick’s model demonstrate Chargaff’s rules?


16.2

What role does complementary base pairing play in the replication of DNA?


16.2

Identify two major functions of DNA pol III in DNA replication.


16.2Why is DNA pol I necessary to complete synthesis of a leading strand? Point out in the overview box in Figure 16.16 (orange book and green book) where DNA pol I would fuction on the top leading strand.


16.2

How are telomeres important for preserving eukaryotic genes?

Concept Check Questions 15.1 Which of Mendel’s laws relates to the inheritance of alleles for a...

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