Concept explainers
The Boundaries of Life
Are viruses alive? Viruses release their genetic material inside cells and then hijack the infected cell's energy supplies and biochemical machinery, turning the cell into a kind of factory that chums out many copies of viral parts. These parts assemble into an army of virus particles. The newly formed viruses then emerge from the host cell, often rupturing it in the process. Some types of viruses, including HIV and the Ebola virus, acquire an outer envelope made of the infected cell's plasma membrane as they emerge. Viruses do not obtain or use their own energy or materials, maintain themselves, or grow. Therefore, viruses do not meet our criteria for life. They do, however, possess a few characteristics of life: Viruses respond to stimuli by binding to specific sites on the cells they attack, and some scientists consider viral replication a form of reproduction. Viruses also evolve, often with stunning speed. How does evolution occur in viruses and other biological entities?
Want to see the full answer?
Check out a sample textbook solutionChapter 1 Solutions
Biology
- Viruses are composed of which type of genetic material inside of a protein shell? a. Not all viruses contain genetic material b. RNA c. DNA d. DNA or RNAarrow_forwardHow might a bacteriophage be used to treat a bacterial infection? – this question relates to question # 2. Address specificity. Why can viruses only infect specific cells? Why would the host cell be safe from infection?arrow_forwardWhat is life? Why are viruses not considered alive? What other things can you think of that are not alive but might be almost alive?arrow_forward
- Figure 17.6 Influenza virus is packaged in a viral envelope, which fuses with the plasma membrane. This way, the virus can exit the host cell without killing it. What advantage does the virus gain by keeping the host cell alive?arrow_forwardAll virus particles, in their infectious form, contain which of the following components? Choose all that apply. Group of answer choices Ribosomes Mitochondria Nuclei Cell membranes Nucleic acids encoding genes Protein capsidsarrow_forwardWhich statement is TRUE? A Viruses are not living things because they don’t have DNA. B Viruses are not living things because they cannot reproduce. C Viruses are not living things because they don’t have organelles. D Viruses are not living things because they are too small to be alive.arrow_forward
- Figure 17.6 Influenza virus is packaged in a viral envelope, which fuses with the plasma membrane. This way, the virus can exit the host cell without killing it. What advantage does the virus gain by keeping the host cell alive?arrow_forward________ can have a genome of either RNA or DNA. a. Bacteria b. Eukaryotes c. Viruses d. Archaeaarrow_forwardExplain why bacteria are alive but viruses are not alive.arrow_forward
- What is the difference between bacteria and viruses? Bacteria are non-living pieces of DNA or RNA; viruses are single-celled organisms Viruses are killed by antibiotics; bacteria are killed by probiotics Bacteria are harmful and are the cause of major human diseases; viruses are often helpful and can kill harmful bacteria Bacteria are single-celled organisms capable of survival and reproduction on their own; viruses cannot survive and replicate without a host cellarrow_forwardWhich of the following statements concerning viruses and human health is false? a-in many diseases caused by viruses, the virus attacks cells as it reproduces b- many viral diseases can be controlled through vaccinations c- some viruses can remain dormant in the body for years before disease symptoms appear d-most viral infections are difficult to treat, but they can be finally destroyed by antibioticsarrow_forwardIs virus a cell?arrow_forward
- Concepts of BiologyBiologyISBN:9781938168116Author:Samantha Fowler, Rebecca Roush, James WisePublisher:OpenStax CollegeBiology Today and Tomorrow without Physiology (Mi...BiologyISBN:9781305117396Author:Cecie Starr, Christine Evers, Lisa StarrPublisher:Cengage LearningBiology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage Learning