Viruses and Bacteria Table of Contents Viruses Bacteria

Viruses and Bacteria Table of Contents Viruses Bacteria Viruses, Bacteria, and Your Health

Viruses and Bacteria - Viruses Deadly Virus USAMRID Click the Video button to watch a movie about deadly viruses.

Viruses and Bacteria Characteristics of Living Things Made of Cells Use Energy Similar Chemistry Respond Grow Reproduce

Viruses and Bacteria - Viruses What Is a Virus? www. cellsalive. com/howbig. htm -A virus is a nonliving particle that enters and then reproduces inside a living cell. -Virus particles are very tiny.

Viruses and Bacteria - Viruses The Structure of Viruses -All viruses have two basic parts: 1. protein coat--that protects the virus 2. inner core--made of DNA or RNA. (Some viruses are surrounded by an outer membrane envelope. )

Viruses and Bacteria The Shape of Viruses come in many shapes: Many-sided (Icosahedron) Example: Polio virus Helical rods Example: Tobacco mosaic virus Robotlike Example: Bacteriophage Spherical or round Example: HIV

Viruses and Bacteria Why are Viruses Nonliving -Nonliving characteristics of viruses: 1. are not made of cells 2. do not use their own energy 3. do not grow or respond 4. can not make food, take in food or produce wastes. -Living characteristics of viruses: 1. contain DNA or RNA 2. contain proteins 3. can multiply---but NOT on their own

Viruses and Bacteria What cells do viruses enter? -Viruses can enter the cells of ANY living organism. -There are viruses that infect plants, animals, fungi, protists and even tiny bacteria cells!!!! -They cause disease and are known as pathogens (any disease-causing agent).

Viruses and Bacteria - Viruses Active and Hidden Viruses Activity Click the Active Art button to open a browser window and access Active Art about active and hidden viruses.

Viruses and Bacteria - Viruses How Viruses Multiply Active viruses enter cells immediately and begin to multiply, leading to the quick death of the invaded cells. The steps are: Attach Release Inject Assemble Copy

Viruses and Bacteria - Viruses How Viruses Multiply Hidden (Latent) viruses “hide” for a while inside host cells before becoming active. Attach Release Inject Hide Assemble Copy

Viruses and Bacteria - Viruses Sequencing As you read, make two flowcharts that show active and hidden viruses multiply. Put the steps in the process in separate boxes in the flowchart, in the order in which they occur. How Active Viruses Multiply Attach: Virus attaches to the surface of a living cell. Inject: Virus injects genetic material into cell. Copy: Cell makes copies of viral proteins and genetic material. Assemble: Viruses assemble. Release: Cell bursts, releasing viruses.

Viruses and Bacteria - Viruses Sequencing As you read, make two flowcharts that show active and hidden viruses multiply. Put the steps in the process in separate boxes in the flowchart, in the order in which they occur. How Hidden Viruses Multiply Attach: Virus attaches to cell. Inject: Virus injects its genetic material. Hide: Virus’s genetic material becomes part of cell’s genetic material. Copy: Cell makes copies viral proteins and genetic material. Assemble: Viruses are assembled. Release: Cell bursts, releasing viruses.

Viruses and Bacteria Common Viral Diseases DNA Viruses Chicken pox Small pox Herpes Parvovirus Bacteriophages Hepatitis B Review Characteristics Of Viruses RNA Viruses Measles Mumps Rubella Polio AIDS Colds Flu Ebola Hepatitis A C and E Viral pneumonia

Viruses and Bacteria Review the steps of an active virus infection by completing the following activity. Virus Infection Review Flipchart Activity

Viruses and Bacteria How Do You Catch a Virus? 1. Contact with an infected person —coughing, sneezing, shaking hands, etc. (colds and flu) 2. Contact with a contaminated object —sharing a drinking cup or utensils, etc. (colds and flu) 3. Insect and animal bites (West Nile and rabies) 4. Contaminated food and water (Rotavirus) 5. Sexual contact and exchange of body fluids (AIDS)

Viruses and Bacteria Fighting Viruses -The Immune System is the body’s only defense against viruses. -Three types of white blood cells and specific antibodies are involved. -There mission: RECOGNIZE DESTROY REMEMBER -Antibiotics and medicines do not work against viruses. Medications only treat symptoms. They can not cure a viral infection.

Viruses and Bacteria Vaccinations -Vaccines—made from weakened or damaged virus particles that can no longer cause infection. 1. Trigger the body’s immune system to prevent infections: not cure them. 2. First vaccine was developed by Dr. Edward Jenner in 1790 to prevent small pox. 3. Are now used to prevent many viral diseases. Show video then notes

Viruses and Bacteria Gene Therapy -Gene Therapy is a new technique in which scientists hope to cure people of genetic diseases using viruses. *Replace a virus’s DNA with information needed to repair a person’s defective genes. *The virus infects the cell with the good information. *Good genes replace bad genes and the person is cured. *Only animal studies have been done so far. *May someday cure diseases like cystic fibrosis.

Viruses and Bacteria HIV and AIDS—acquired immune deficiency syndrome First known case: Africa 1959. HIV—human immunodeficiency virus -The Virus that causes AIDS -First seen in 1978: Identified and named in 1983 -Attacks the cells of the immune system so the body cannot fight infections. -It can take up to 10 yrs for an HIV infected person to develop full-blown AIDS. -RNA virus, so it mutates rapidly -Work has begun on a vaccine: has not been successful.

Viruses and Bacteria The Spread of Viruses -World-wide the spread of viruses is increasing rapidly. -Why are previously rare viruses, like ebola, being reported in new countries? 1. Global travel and trade 2. World wide population growth. 3. Humans exploring remote areas.

Viruses and Bacteria End of Section: Viruses

Viruses and Bacteria - Bacteria The Bacterial Cell -Bacteria are prokaryotes. *They have no nucleus. *Their DNA floats free in a gel-like substance known as cytoplasm. *Surrounded by a cell membrane and cell wall. *Some move using taillike structures known as flagella. (one or many) *Ribosomes also float in the cytoplasm. They make proteins.

Viruses and Bacteria Shapes of Bacteria Three basic shapes: 1. Bacilli—rod-shaped 3. Spirilla—spiral-shaped 2. Cocci—sphere-shaped

Viruses and Bacteria Obtaining Food and Energy -Some bacteria are autotrophs (make their own food). 1. Photoautotrophs—use sunlight to make food Example: Cyanobacteria (blue-green bacteria)--all contain chlorophyll and are found in lakes and ponds (usually as a cloudy scum). Some have other pigments that make them red, yellow or black. (Red Sea named for red cyanobacteria). 2. Chemoautotrophs—use the energy from chemicals in their environment to make their food. They live deep in the mud or in extreme environments like hot springs.

Viruses and Bacteria Obtaining Food and Energy -Other bacteria are heterotrophs (cannot make food). *They feed on many different things. *Some are important saprophytes—feeding on decaying organisms.

Viruses and Bacteria Reproduction -Most bacteria reproduce by binary fission. *Binary fission is a type of asexual reproduction where one cell divides into two identical cells. *Some bacteria can double their population every 20 minutes if conditions are just right. This means that one cell can become one billion in just 10 hrs.

Viruses and Bacteria Sexual Reproduction -Some bacteria use a simple form of sexual reproduction known as conjugation. *Conjugation does not increase the number of bacteria cells. It just creates new combinations of genetic material to be passed on when new cells form through fission.

Viruses and Bacteria - Bacteria More on Bacteria Click the PHSchool. com button for an activity about bacteria.

Viruses and Bacteria - Bacteria Population Explosion Suppose a bacterium reproduces by binary fission every 20 minutes. The new cells survive and reproduce at the same rate. This graph shows how the bacterial population would grow from a single bacterium.

Viruses and Bacteria - Bacteria Population Explosion Reading Graphs: What variable is being plotted on the horizontal axis? What is being plotted on the vertical axis? Horizontal axis–time (minutes); vertical axis– number of bacterial cells.

Viruses and Bacteria - Bacteria Population Explosion Interpreting Data: According to the graph, how many cells are there after 20 minutes? One hour? Two hours? 2 cells after 20 minutes; 8 cells after one hour; 64 cells after two hours.

Viruses and Bacteria - Bacteria Population Explosion Drawing Conclusions: Describe the pattern you see in the way the bacterial population increases over two hours. The number of cells doubles with each division.

Viruses and Bacteria - Bacteria Population Explosion Predicting: Do you think the bacterial population will continue to grow at the same rate? Why or why not? Not likely. The bacteria will continue to reproduce at this rate only as long as the conditions are favorable.

Viruses and Bacteria Role of Bacteria in Nature -Bacteria can be helpful, harmful, or harmless. Helpful Bacteria: *Produce oxygen in the air *Used in food production (yogurt, cheese, pickles, sauerkraut, sour cream) *Decomposed dead organisms *Turn nitrogen gas into usable nitrogen products for plants (nitrogen-fixing bacteria) *Clean up oil spills *Help digest food and make vitamins *Make medicines Harmful Bacteria: *Spoil food *Cause disease (Examples: strep throat, botulism, diptheria, tetanus, whooping cough, TB, Lyme disease, and anthrax) Harmless Bacteria: *Live among us totally undetected. Do not hurt or help.

Viruses and Bacterial Diseases Bacterial diseases are spread in the same manner as viral diseases: Contact with an infected person (TB and strep throat) Contact with a contaminated object (strep throat and tetanus) Insect and animal bites (Lyme disease) Contaminated food and water (botulism) Sexual contact and exchange of body fluids (Hepatitus C)

Viruses and Bacteria Fighting Bacteria -Antibiotics can be used to kill bacteria. *Antibiotic resistance —some bacteria can survive in the presence of antibiotics. They multiply and the disease continues. This makes some diseases difficult to treat. -Preventing infections is important *Vaccines can be used for both bacterial and viral infections. *Hand washing *Don’t share cups and utensils *Cook and store foods properly *Eat healthy, get rest, drink fluids, & exercise

Viruses and Bacteria - Viruses, Bacteria, and Your Health Antibiotic Resistance Click the Video button to watch a movie about antibiotic resistance.

Viruses and Bacteria End of Section: Bacteria

Viruses and Bacteria - Viruses, Bacteria, and Your Health Common Bacterial Diseases Many bacterial diseases can be cured with antibiotics.

Viruses and Bacteria - Viruses, Bacteria, and Your Health Common Viral Diseases Unlike with bacterial diseases, there are currently no medications that can cure viral infections.

Viruses and Bacteria - Viruses, Bacteria, and Your Health Using Prior Knowledge Look at the section headings and visuals to see what this section is about. Then write what you already know about diseases caused by viruses and bacteria in a graphic organizer like the one below. As you read, write what you learn. What You Know 1. 2. You can catch a cold from somebody who has one. Some diseases can be treated with medicines. What You Learned 1. 2. You can catch diseases through contact with an infected person, a contaminated object, an infected animal, or an environmental source. Antibiotic resistance results when some bacteria are able to survive in the presence of an antibiotic.