Concept explainers
Briefly describe the insect defense system against infecting RNA viruses.
Why does this system not attack the RNA of normal insect cells?
a.
To explain: Insect defense system against infecting RNA viruses.
Introduction: The defense system in insects is innate immunity. Like humans, insect is also prone to infectious agents like bacteria, virus, parasites, and fungi on a daily basis. To protect themselves from the pathogens, the insects develop a potential immune system. The innate immune system of insects is divided into two types, namely cellular immunity and systemic immunity.
Explanation of Solution
Insects, when exposed to infectious agents, synthesize enormous amounts of antimicrobial peptides to fight with that infection. One such peptide is Dicer-2 enzyme, which recognizes the double-stranded viral RNA and cuts them into short fragments. The Argo protein complex, known to involve in gene silencing, binds with the RNA fragment, which in turn binds with the complementary viral mRNA molecule. The Argo complex prevents the translation by cleaving the viral mRNA.
b.
To explain: Insect defense system’s inability to attack the normal insect cells.
Explanation of Solution
The RNA molecules in eukaryotic cells are generally single stranded. However, the viral RNA is double-stranded. Therefore, the Dicer enzyme cannot recognize the single-stranded host RNA. The difference in the RNA strands made the insect’s immune system to distinguish between the self and non-self cells.
Want to see more full solutions like this?
Chapter 43 Solutions
Study Guide for Campbell Biology
- The diagram below shows the Covid-19 virus with its spike protein. It also shows the area on the spike protein which binds to the ACE2 receptor (receptor binding domain). Corona Virus Receptor Binding Domain (RBD) Spike Protein In order to get into a cell, the Covid-19 virus needs to bind to the ACE2 receptor. Once bound it is brought into the cell. These receptors are found on cells making up various tissues (oral and nasal mucosa, nasopharynx, lung, stomach, small intestine, colon, skin, lymph nodes, thymus, bone marrow, spleen, liver, kidney, and brain). The symptoms for Covid-19 are linked to the tissue cells the virus infects. To the right is a diagram showing the biding of the spike protein to the ACE2 receptor. SARS-COV-2 Spike (S) Host Cell ACE2 acerarrow_forwardModerna and Pfizer vaccines for COVID-19 use mRNA to the Spike protein combined with lipids. Which of the following is/are advantages of this type of vaccine compared to an inactivated virus vaccine? Select ALL correct answers. a) The vaccine is more stable for transport. b) The vaccine does not contain the virus so it cannot give you COVID-19. c) The vaccine can be rapidly produced in a slightly different form to protect from variants of SARS-CoV-2. d) The vaccine does not need a booster.arrow_forwardSome Pattern Recognition Receptors (PRRs) recognize nucleic acids, like RNA or DNA. Since our own cells contain human RNA and DNA, the activation of innate immune pathways by these PRRs must rely on additional criteria to discriminate self from nonself. Additional criteria include everything EXCEPT: The subcellular location of the RNA The presence of adenosine residues in viral RNA The methylation state of the DNA Unique structures found on viral RNA The subcellular location of the DNAarrow_forward
- Toll-like receptors represent an ancient pathogen-recognition system. The first pattern recognition receptor (PRR) important in innate immune responses was discovered in the fruit fly Drosophila melanogaster. Stimulation of this receptor, called Toll, induces: The synthesis of prostaglandins and leukotrienes The inflammatory response in Drosophila hemolymph vessels The production of antimicrobial peptides The recruitment of phagocytic cells to the site of infection The activation of Drosophila complementarrow_forwardDescribe Covid-19, it’s mechanism of entry, and it’s deleterious effects. Be specific about receptor type used for viral entry.arrow_forwardSerum from individuals with high levels of antibody to SARS-CoV2 has been used to treat patients with severe COVID-19. What is ONE way (there are several) that passive immunization with the antibody to the virus could help these patients? HINT: think about what opsonization with antibody could do for the innate immune response.arrow_forward
- a. Which type of viruses can be directly used for translation? a) dsRNA b) Positive ssRNA c) Retroviruses d) Negative ssRNA b. An antiviral drug specifically modifies viral receptors on a eukaryotic host cell. How might this affect the viral reproductive cycle? It would enhance the process of viral apoptosis It would result in the degeneration of the viral capsid It would facilitate the process of viral endocytosis It would prevent the virus from attaching to the host cellarrow_forwardWhat properties make ribavirin an effective antiviral compound? Give an example of a virus and yay is inhibited by ribavirin. Thank you!arrow_forwardWhich of the following would you anticipate would be secreted through the Type III secretion system during infection? a secondary messenger effector that is unable to cross the host cell membrane, such as the AexT protein that disrupts the host cell cytoskeleton the superantigen TSST that is responsible for the signs and symptoms associated with toxic shock syndrome a pore-forming cytolytic toxin, such as a hemolysin not enough information to determine the AB toxin responsible for the flaccid paralysis associated with botulismarrow_forward
- what impact could a mutation that makes the binding to the ACE-2 receptors stronger have on a virus's ability to enter cells and transmit the disease further on?arrow_forwardWhich of the following is false when considering the CCR5Δ32 mutation? a) The mutation prevents the entry of HIV-1 into a T cell. b) The deletion that produced CCR5Δ32 caused a frameshift which extends the length of the protein product. c) CCR5Δ32 prevents infection by HIV-1 in homozygotes but only delays the onset of HIV symptoms in heterozygotes. d) The protein product produced by CCR5Δ32 is altered in such a manner that it cannot embed in the cell membrane.arrow_forwardDecreasing the amount of cytokine produced by the body would most directly prevent what event during the progression of COVID-19 in its host? A). Early viral infection of host cells. B). Replication of infected cells. C). Excessive damage to lung cells by the hot immune system. D). Transmission of the virus from one host to another.arrow_forward
- Human Anatomy & Physiology (11th Edition)BiologyISBN:9780134580999Author:Elaine N. Marieb, Katja N. HoehnPublisher:PEARSONBiology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStaxAnatomy & PhysiologyBiologyISBN:9781259398629Author:McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa StouterPublisher:Mcgraw Hill Education,
- Molecular Biology of the Cell (Sixth Edition)BiologyISBN:9780815344322Author:Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter WalterPublisher:W. W. Norton & CompanyLaboratory Manual For Human Anatomy & PhysiologyBiologyISBN:9781260159363Author:Martin, Terry R., Prentice-craver, CynthiaPublisher:McGraw-Hill Publishing Co.Inquiry Into Life (16th Edition)BiologyISBN:9781260231700Author:Sylvia S. Mader, Michael WindelspechtPublisher:McGraw Hill Education