Genetics and Inheritance

A scientist is studying a newly discovered species of bacteria. They observe that the bacteria contain a plasmid with a gene that confers resistance to an antibiotic. Which of the following mechanisms is most likely responsible for the rapid spread of antibiotic resistance in this bacterial population?

In a population of butterflies, wing color is determined by a single gene with two alleles: 'B' for blue and 'b' for brown. Blue butterflies are dominant. If 16% of the population is brown, what percentage of the population are heterozygous carriers of the brown allele, assuming the population is in Hardy-Weinberg equilibrium?

A researcher is studying a human pedigree for a rare genetic disorder. They observe that the disorder appears in every generation, and that affected fathers always pass the trait to their daughters but never to their sons. Which of the following inheritance patterns is most likely?

Two parents, both with the genotype Bb for a particular trait, have a child. What is the probability that the child will also have the genotype Bb?

In cats, the gene for coat color is located on the X chromosome. The allele XB codes for black coat color, and the allele XO codes for orange coat color. Heterozygous females (XBXO) exhibit a tortoiseshell coat color. If a black male cat is mated with a tortoiseshell female, what percentage of the male kittens are expected to be orange?

A plant breeder crosses a true-breeding tall plant with a true-breeding dwarf plant. All the F1 generation plants are tall. When the F1 plants are allowed to self-pollinate, the F2 generation consists of 75% tall plants and 25% dwarf plants. Which genetic principle does this experiment demonstrate?

A population of birds is undergoing natural selection. Birds with larger beaks are better able to crack open tough seeds, while birds with smaller beaks are better at collecting small insects. What type of selection is most likely occurring in this population?

Which of the following best describes the role of tRNA in protein synthesis?

A geneticist discovers a new mutation in yeast that affects the splicing of pre-mRNA. Which of the following cellular processes will be most directly affected by this mutation?

A researcher is studying a population of frogs and observes that the frequency of a particular allele changes significantly over a short period due to a chance event (a flash flood). Which of the following mechanisms of evolution is most likely responsible for this change?