Viruses VS. Cells
By Caitlin Kresta
Types of viruses:
Plant and Animal Cell:
Characteristics of Life
- they grow and develop
- have a genetic code
- they respond to the environment
- made of cells
- able to reproduce
- maintain homeostasis
- obtain and use material energy
Of these eight characteristics, viruses only share two. Viruses contain genetic material such as DNA or RNA, and they pass the material onto their offspring. As a result of having genetic material, small mutations can occur over time, allowing the virus to evolve.
1. Describe the typical structure of a virus. What is a virus made of? What biomolecules
would you find in a virus?
The basic virus structure consists of a strand of DNA or RNA, Enzymes, and a protein coat (capsid). Some more complex viruses have an outer lipid membrane called the envelope. This simple structure has only the biomolecules nucleic acids, proteins, and sometimes lipids.
2. Discuss the different ways viruses gain entry into a cell.
There are two ways a virus may gain entry to a cell. One way is by the virus having specific protein spikes on the envelope that match the protein on the outside of the host cell. The envelope then fuses together with the host's cell membrane and allows the DNA to enter the cell. The second way is by absorption. The host cell recognizes the viruses proteins, creates a vesicle around the virus, and absorbs it.
3. Explain why the Ebola virus would not infect a tobacco plant.
Viruses are specific when it comes to the cells they attack. For example, a virus with a capsid or envelope that was structured to imitate an animal's' cell membrane, would not try to enter a plant cell.
4. Name five viruses and the type of cell that they attack.
HIV: attacks Helper-T cells
Influenza: attacks Respiratory Cells
Ebola: attacks Fibroblasts of any type
Type 1 Herpes: cells of the mouth and lips
Type 2 Herpes: cells of the genitalia
5. You have been diagnosed with the flu. Explain why a doctor will not provide you
with a prescription for antibiotics in order to cure your infection.
Antibodies fight viruses, and by taking antibiotics, which kill antibodies you would actually be helping the virus spread. Viral infections and Bacterial infections are extremely different, which is why you should not take medication that isn't prescribed for your specific infection.
6. How is it that a person can be infected with a virus such as HIV and not exhibit
HIV is a virus that goes through the Lysogenic Cycle. This means that the host call can go months, even years without the virus entering the Lytic Cycle. Once it enters the Lytic Cycle though, then you experience symptoms (AIDS)