Comparing Viruses to Cells

By Maria Soria and Vivian Liu

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In the lytic cycle, viruses find a host cell, reproduces thousands/millions of times within hours, weakens the cell wall enough that it will burst open, or lyse, then the virus copies are released to go infect other cells. This process results in the death of the infected cells. Step one: Exposure. A virus can be exposed to a host in many different ways. They can enter through a cut, a mosquito bite, direct contact with the stomach, nostrils, or genitals, meaning you can get a virus from food contamination/ food poisoning, breathing it in from the air, or through sexual contact. Step two: Entry. Once the virus is in your body, it finds a host cell to physically attach to. After attaching itself to the cell membrane, the virus creates a hole in the membrane and injects its genome into the cell. Step three and four: Replication and Assembly. The virus is now in your cell. The virus has now gained access to the genetic material inside your cell and it can now take over your cell and do what it wants with it. The virus starts making thousands or millions of replications of itself inside your cel, using the cells parts. The virus weakens the cell membrane and gets ready to be released to infect other cells. Step five: Release. This is the last step in the cycle. The virus causes the cell membrane to lyse and the millions of copies are released to go infect millions of other cells, which make more copies and release them, etc.
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The lysogenic cycle us when only a few virions are being released at a time. A virus that develops lysogenically can live in its host for years and survive and replicate itself. Step one: Exposure/Attachment and Injection. A virus can enter the body through a cut, a mosquito bite, or direct contact with mucus membranes. The virus attaches to the hosts membrane and makes a hold to injects its genome. Step two and three: Virus circulates and integrates and binary fission occurs. The virus then attaches to the DNA in the cell and its replicated when binary fission occurs. This is when the bacteria cell spits into two genetically identical cells. The lysogenic cycle is much slower than the lytic cycle. Step four-six: lytic cycle. After the virus has duplicated with the cells enough ( long period of time ), the virus switches cycles and the lytic cycle starts to happen from the replication step. The main difference between the two cycles is the in the lytic cycle, the genome only enters the cytoplasm and starts doing its thing while in the lysogenic cycle, the genome goes into the nucleus. Another example of a virus that develops through the lysogenic cycle is HIV/AIDS.

Characterstics of Life-Compare and Contrast

1. All living things are composed of one or more cells.

Viruses are not made up of cells, they are much simpler than cells. However, they do contain gentic material like other living things.


2. Reproduction

Viruses are able to reproduce witht their , but reproduction requires the aid of a host cell. Viruses will either go through the lytic or lysogenic cycle to reproduce/ make copies of themselves. The lytic cycle will copy the virus much quicker than the lysogenic cycle will.


3. Maintains Homeostasis

Viruses don't maintain homeostasis because they are not made of and don't undergo regular cell activities. Homeostasis involves keeping your body balanced while viruses depend on the host to survive.


4. Respond to the Environment

Viruses respond to their environment, but only with the help of the host because they are not living. The virus responds when it enters the body and replicated when it invades the cells. Basically, the viruses responses depends solely on the host cell.


5. Growth and Development

Viruses don't have this characteristic because the replication of a virus is simply a recreation of the same thing, so there is no sign of growth or development. Living cells actaully change in size and makeup. Also, there are different kinds of cells being produced, not the same one over and over.


6. Obtains and uses Energy

Viruses don't obtain energy because they only inject their genetic material into the host. Everything that a virus does is made possible by ATP found in the host cell, so that is how viruses are powered.


7. Evolution

Viruses do exhibit evolution because the few viruses that are resistant to a certain immune response will make more copies of their kind, which results in a population of stronger and more resistant virus.


8. Genetic Code

Viruses contain DNA, which is their genetic makeup that they will later inject into the host cell.

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Questions

4. Some viruses are cowpox, HIV, influenza, Ebola, and measles. They all attack animal/human cells.

5. Antibiotics don't work on the flu because antibiotics only work for sicknesses caused by bacterial infections. Flus and colds are caused by viruses, so antibiotics don't work on them.

6. Viruses like HIV/AIDS develop through the lysogenic cycle, meaning that the virus hides inside the DNA and replicates when the cell does. This process is slower and the symptoms will start showing when the cycle changes from lysogenic to lytic.