Can antibiotics be used to cure an illness caused by a virus?
Viruses can be harmful.
Viruses may be helpful.
Characteristics used to classify viruses.
*Knowing the structure of a virus gives hints about how the virus interacts with a cell to initiate the infectious process and how the structure of the viral proteins allows interaction with the immune system. From this information, strategies to abort virus infection might be advised.
Compare Lytic and Lysogenic Cycles:
All viruses invade a host cell and reproduce through one of these cycles.
Size Of Viruses:
Viruses are very small, ranging in size from 20 nanometers to 250 nanometers. A nanometer is equal to 0.00000004 inch (4X10-8 in). The smallest of all bacteria is about the size of the largest virus. This picture shows round virus particles along with rod-shaped bacteria cells.
Viruses are usually easy to destroy while outside living organisms. Outside the body, the "AIDS" virus, HIV, can be destroyed with a solution of bleach that is almost weak enough for you to drink. But once inside a host, most substances that destroy the virus are also harmful to the host organism. For this reason, viral infections in animal cells can be extremely hard to cure. Viral infections in plant cells are almost impossible to cure.
Compared to the number of vaccines developed to treat bacterial diseases, there are very few vaccines for viral infections. Virus vaccines are made with either inactivated or attenuated viruses. Inactivated viruses do not replicated in a host cell. Attenuated viruses have been genetically altered so they are not able to cause disease. The first viral vaccinations were for measles, mumps, and rubella. There are now vaccines for hepatitis A and B, chickenpox, smallpox, and rabies.
Your body does have some natural ability to inhibit viral infections. There are two limited ways the body fights viruses:
Day 1-2 Assignment - Viruses
This assignment must be turned in by the end of class tomorrow to receive credit.
How quickly can a virus replicate in a host organism? Complete the following activity to determine how many viruses an organism might be infected with after a half hour, after 2 hours, after 4 hours.
- Do you have the correct rubric, "paper rubric" for paper graphs or "Excel rubric" for Excel graphs?
- Remember, the rubric always goes on top, then graph, then worksheet.
How are viral infections in plants usually stopped?
Day 3 Assignment - Viruses
This assignment must be turned in by the beginning of class tomorrow to receive credit.
1. As you view part 1 of this video write down and answer the four discussion questions at the beginning of this part.
Part B: Use this weeks information about viruses to answer the following questions.
- Are viruses considered living? Explain your answer.
- Describe how viruses are classified?
- List the names of 3 different types of viruses.
- What is the difference between a temperate and virulent virus.
- What is the lytic cycle?
- How is the lysogenic cycle different from the lytic cycle?
- Name 3 diseases caused by viruses and give a brief summary about each.
- Why is it hard to cure viral infection?
- Describe different ways we try to control viruses?
- Describe how your body might fight Viruses?
What is the Flu?
The flu is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness, and at times can lead to death. While most healthy people recover from the flu without complications, some people, such as older people, young children, and people with certain health conditions, are at high risk for serious complications from the flu.
Be Aware of Common Flu Symptoms
The flu usually starts suddenly and may include these symptoms:
- Fever (usually high)
- Tiredness (can be extreme)
- Sore throat
- Runny or stuffy nose
- Body aches
- Diarrhea and vomiting also can occur but are more common in children.
These symptoms are referred to as "flu-like symptoms." A lot of different illnesses, including the common cold, can have similar symptoms.
Know the Risk from the Flu
Some of the complications caused by the flu include bacterial pneumonia, dehydration, and worsening of chronic medical conditions, such as congestive heart failure, asthma, or diabetes. Children and adults may develop sinus problems and ear infections.
Know How the Flu Spreads
The flu spreads in respiratory droplets from coughing and sneezing. It usually spreads from person to person, though occasionally a person may become infected by touching something with virus on it and then touching their mouth or nose.
Adults may be able to infect others 1 day before getting symptoms and up to 7 days after getting sick. So it is possible to give someone the flu before you know you’re sick as well as while you are sick. See this site for more information on the flu
Day 4 Assignment - Viruses
This assignment must be turned in by the end of class day after tomorrow to receive credit.
1. As you view part 2 of this video write down and answer the four discussion questions at the beginning of this part.
Part B: Pick one specific virus and research the following:
1. What is the name of the virus?
2. Describe the virus, name its parts. (can include a diagram)
3. Is it a DNA or RNA type virus?
4. Is it harmful?
5. What type of organism does it infect and what part?
6. What symptoms does the virus cause?
7. How does the virus replicate itself?
8. It what geographical region has it been found? Any area of origin?
9. What is used to fight back against this type of virus?
Antibiotics have no effect on viral infections.