BSC 114-Exam 4 Practice Questions With Multiple Choices And Answers 100% Verified

Why are viruses referred to as obligate parasites? - correct answers They cannot reproduce outside of a host cell. They lytic cycle of bacteriophage infection ends with the___. - correct answers rupture of the bacterium As a result of the lytice cyle, ___. - correct answers the host cell's DNA is destroyed The genetic material of HIV consists of ___. - correct answers single-stranded RNA What is the function of reverse transcriptase? - correct answers It catalyzes the formation of DNA from an RNA template. What is the source of a viral envelope? - correct answers hose cell membrane Double-stranded viral DNA is incorporated into a host cell as a ___. - correct answers provirus Which of the following is a characteristic of the lytic cycle? - correct answers A large number of phages is released at a time. The unpaired nucleotides produced by the action of restriction enzymes are referred to as ___. - correct answers sticky ends What is the enzymatic function of restriction enzymes? - correct answers to cleave nucleic acids at specific sites Bacteria containing recombinant plasmids are often identified by which process? - correct answers exposing the bacteria to an antibiotic that kills cells lacking the resistant plasmid In 1997, Dolly the sheep was cloned. Which of the following processes was used? - correct answers fusion of an adult cell's nucleus with an enucleated sheep egg, followed by incubation in a surrogate Why is golden rice pale yellow in color? - correct answers It is rich in beta-carotene. Which of these is a symptom of vitamin A deficiency? - correct answers blindness During drought years on the Galapagos, small, easily eaten seeds become rare, leaving mostly large, hard-cased seeds that only birds with large beaks can eat. If a drought persists for several years, what should one expect to result from natural selection? - correct answers More small-beaked birds dying than larger-beaked birds. The offspring produced in subsequent generations have a higher percentage of birds with large beaks. In a hypothetical environment, fishes called pike-cichlids are visual predators of algae-eating fish (i.e., they locate their prey by sight). If a population of algae-eaters experiences predation pressure from pike-cichlids, which of the following should least likely be observed in the algae-eater population over the course of many generations? - correct answers Selection for larger female algae-eaters, bearing broods composed of more, and larger, young Which statement best describes the evolution of pesticide resistance in a population of insects? - correct answers Offspring of insects that are genetically resistant to the pesticide become more abundant as the susceptible insects die off. Of the following anatomical structures, which is homologous to the wing of a bird? - correct answers Flipper of a cetacean Ichthyosaurs were aquatic dinosaurs. Fossils show us that they had dorsal fins and tails, as do fish, even though their closest relatives were terrestrial reptiles that had neither dorsal fins nor aquatic tails. The dorsal fins and tails of ichthyosaurs and fish are - correct answers examples of convergent evolution, and adaptions to a common environment Within a few weeks of treatment with the drug 3TC, a patient's HIV population consists entirely of 3TC-resistant viruses. How can this result best be explained? - correct answers A few drug-resistent viruses were present at the start of treatment, and natural selection increased their frequency. Which of the following has the largest genome and the fewest genes per million base pairs? - correct answers Homo sapiens (humans) Why might the cricket genome have 11 times as many base pairs than that of Drosophila melanogaster? - correct answers Crickets must have more non-coding DNA. One of the characteristics of retrotransposons is that - correct answers they code for an enzyme that synthesizes DNA using an RNA template. Which of the following is a major distinction between a transposon and retrotransposon? - correct answers A transposon moves via a DNA intermediate and retrotransposon via RNA intermediate. Multigene families are - correct answers identical or similar genes that have evolved by gene duplication. Several of the different globin genes are expressed in humans, but at different times in development. What mechanism could allow for this? - correct answers differential gene regulation over time Which of the following most correctly describes a shotgun technique for sequencing a genome? - correct answers cloning several sizes of fragments into various size vectors, ordering the clones, and then sequencing them Homeotic genes contain a homeobox sequence that is highly conserved among very diverse species. The homeobox is the code for that domain of a protein that binds to DNA in a regulatory developmental process. Which of the following would you then expect? - correct answers That homeotic genes are selectively expr