Question1) What is the function of reverse transcriptase in retroviruses? O a) It hydrolyzes the host cell's DNA. 0 b) It uses viral FINA as a template for DNA synthesis. 0 c) It converts host cell RNA into viral DNA. 0 d) It translates viral RNA into proteins. 0 e) It uses viral RNA as a template for making complementary RNA strands. Question 2 1 pts Electron micrographs of a time course of HSV infection show virus particles initially reacting with cell surface receptors. This is later followed by viral capsids docking with nuclear pores. Afterward, the capsids go from being full to being "empty." Which of the following best fits these observations? 0 a) Viral capsids are needed for the cell to become infected; only the capsids enter the nucleus. 0 b) The viral envelope is not required for infectivity, since the envelope does not enter the nucleus. 0 c) Only the genetic material of the virus is involved in the cell's infectivity, and is injected like the genome of a phage. 0 d) The viral envelope mediates entry into the cell, the capsid facilitates transport of the genome to the nucleus, and the genome is all that enters the nucleus. 0 e) The viral capsid mediates entry into the cell, and only the genomic DNA enters the nucleus, where it may or may not replicate.

Question 3 1 pts Viruses use the host cell machinery to replicate. However, some viruses replicate their genomes by a mechanism that host cells cannot support. How can these types of viruses infect and replicate in their host, when the host cell cannot perform a particular role that the virus requires? 0 a) The viral genome encodes the specialized enzymes that the host does not have. 0 b) The virus causes mutations in the human cells, resulting in the formation of new enzymes that are capable of performing these roles. O c) The virus infects only those cells and species that can perform all the replication roles necessary. 0 cl) Viruses can stay in a quiescent state until the host cell evolves this ability. 0 e) All of the above have been frequently observed. Question 4 1 pts Which of the following would happen if a drug that blocks the action of viral DNA polymerase was introduced into cells just prior to infection with a herpesvirus? 0 a) The virus would not be able to enter the host cell 0 b) The newly formed virions would be unable to leave the host cell 0 c) Viral proteins would not be made and the virus would be unable to replicate 0 cl) New virus particles would be unable to assemble in the cell.

Questions 6 and 7: Imagine that you can engineer an mRNA encoding a protein with two conflicting address tags, each of which specifies a different compartment in the cell. You express your engineered mRNA in the cell and look to see where the translated protein product ends up in the cell. Question 6 1 pts Suppose your mRNA encodes a nuclear localization signal AND a signal sequence/peptide. The protein product would be found in which of the following? O a) Nucleus ( b) Rough endoplasmic reticulum O c) Both O d) Neither Question 7 1 pts Suppose your mRNA encodes a mitochondrial presequence AND a Golgi retention sequence. Where would the protein end up in the cell? O a) Mitochondrion O b) RER O c) Golgi O d) All 3 places

Question 8 1 pts Upon analyzing a sample of cells from a patient, you find the lysosomes to be filled with undigested material. This observation makes you think that the lysosomes are not functioning properly. Which of the following could account for the defective lysosomes (choose all that apply)? ( a) defect in transport of small molecules from digested materials into the cytosol ( b) defect in the mannose-6-phosphate receptor in the Golgi apparatus ( c) defect in the lysosomal proton pump O d) defect in a digestive enzymes ( e) defect in the process of adding a mannose-6-phosphate signal to lysosomal enzymes ( f) defect in receptor-mediated endocytosis

Question 9 1 pts The schematic below shows the amino acid sequence of several proteins in cartoon format. The white boxes represent 20-30 hydrophobic amino acid stretches and the dark boxes represent domains with mostly hydrophilic amino acids. NHz-l-IIIIIII-COOH Histone deacetylase is represented by which of the amino acid sequences above (A-D)? 0A OB Question 10 1 pts Scientists have found that secretory proteins are smaller than their coding sequences predict. Which oi the following best explains why this is so? 0 a) Secretory proteins are generally smaller than proteins within the cell. 0 b) Secretory proteins are posttranslationally cleaved to a mature form prior to secretion. 0 c) The RNA encoding secretory proteins is always spliced prior to translation. 0 d) Secretory proteins are trimmed as they pass through the plasma membrane.

Question 5 1 pts You are characterizing the genome of a newly discovered RNA virus. You isolate viral mRNA from cultured cells infected with the virus. When you compare this mRNA to the viral genome, you find that they are complementary. What does this tell you? O a) This virus has a positive-sense genome. O b) The virus does not use DNA or RNA. O c) This virus has a negative-sense genome.

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