Concept explainers
The Boundaries of Life
If viruses aren't a form of life, what are they? A virus by itself is an inert particle that doesn't approach the complexity of a cell. The simplest virus, such as that causing smallpox (FIG. 1.14), consists of a protein coat that surrounds genetic material. The uncomplicated structure of viruses, coupled with amazing advances in
Want to see the full answer?
Check out a sample textbook solutionChapter 1 Solutions
Biology: Life on Earth with Physiology (11th Edition)
- Different types of viruses have different types of genomes- some are double-stranded DNA, some are single-stranded DNA, some are double-stranded RNA, and some are single-stranded RNA. The Ebola virus genome is a piece of single-stranded RNA. Given this piece of information, do you expect it to see %Adenine = %Uracil and the %Guanine = %Cytosine? Why or why not?arrow_forwardBiology 1. There is evidence to dispove Crick's (1958) Central Dogma of Molecular Biology. one such evidence is how the coronavirus replicates genetic information. Explain fully how this process disproves Crick's Central Dogma 2. Describe how subgenomic RNAs are unique physically compared to regular RNA strands. Explain fully the benfit of this adaptation for viruses..arrow_forwardviruses:1. Why must primary cell cultures be restarted every so often when preparing primary cell cultures to observe morphological changes caused by cells infected by a virus? Why are tumor cells preferred? 2. Why are non-enveloped viruses generally more resistant to disinfectants than are enveloped viruses? 3. A public health physician isolated large number of phages from rivers used as a source of drinking water in western Africa. They physician is very concerned that humans might become ill from drinking this water, although she knows that the phages specifically attack bacteria. Why is she concerned?arrow_forward
- All 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 biological system contains a protein nucleocapsid surrounding 2 antiparallel polynucleotide strands (held together by hydrogen bonds), with deoxyribose sugars, but no ribose sugars? a single-stranded RNA viroid (like avocado sun blotch viroid) a double-stranded RNA virus (like the reovirus family) a single-stranded DNA virus (like fX174 virus of E. coli) a double-stranded DNA virus (like the smallpox virus) a single-stranded RNA virus (like tobacco mosaic virus)arrow_forwardWhy are viruses are not regarded as true living cells?arrow_forward
- Are viruses living? Why or why not?arrow_forwardThe real-world scenario that we are going to look as is as Shakespeare would say “Viruses are living or not living - that is the question!” Viruses must be living since they can cause cancer and warts.arrow_forwardViruses display many of the characteristics of living organisms. In particular, they reproduce, creating new virus particles. During reproduction, viruses make copies of their genetic material, and some of the copies contain mutations that are beneficial to the virus. For example, HIV (human immunodeficiency virus), the virus that causes the disease AIDS (acquired immunodeficiency syndrome) mutates so often that its surface proteins change faster than we can develop antiviral drugs. New drug-resistant strains of HIV are appearing constantly. However, viruses can reproduce only after entering a living cell of an organism, because viruses hijack the cell’s machinery and use it to produce new viruses. Where does that combination of characteristics place viruses on the scale of nonlife to life? Are viruses living organisms? Nonliving? If neither of those categories fits the properties of viruses, how should they be classified?arrow_forward
- State 3 simple ways in which RNA polymerase is the same as DNA polymerase.arrow_forwardAt this point we know that DNA is located inside the nuclei (plural of nucleus) of cells, but would you eat DNA?arrow_forwardCompare and contrast bacteria cells and viruses. Give three similarities and three differences.arrow_forward
- Biology 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