Bacteria & Viruses

What is the definition of Disease? Any change that disrupts the normal function of one or more body systems. What are Noninfectious diseases? Noninfectious diseases: Diseases caused by exposure to certain chemicals or traits that are inherited. What are infectious diseases? Infectious diseases: Diseases caused by a pathogen . What is a pathogen? any microbe that causes disease. (i.e. bacteria, virus, fungi, protozoa (parasite)).

What are the Characteristics of Organisms? All living things are composed of one or more cells All living things perform certain chemical processes such as growth and digestion All living things can reproduce All living things either make their own nutrients or ingest nutrients from the environment All living things respond to stimuli such as light and touch All living things evolve & adapt All living things maintain homeostasis

Bacteria What are Prokaryotes? Most microbes are prokaryotes, i.e. Single-celled Exist almost every where on earth Cells that do not have a nucleus Contains a rigid cell wall, cytoplasm and ribosomes. Identifying Prokaryotes: -Cell Shape -Cell Wall -Movement -How they get their energy

What are the different Bacterium Shapes? Cocci ~ Sphere shaped bacteria Bacillium ~ Rod shaped bacteria Spirillum ~ Spiral shaped bacteria Motility: Flagellum~ Leg or whip-like structure that help to propel the bacterium.

Eubacteria Kingdom Eubacteria a. most common type of bacteria b. live almost everywhere (in side or outside the body, fresh water, salt water, land, etc) c. very diverse d. have special layer in cell wall called peptidoglycan

Archaebacteria a. lives in harsh environments (ex: hot springs, oxygen-free environments, or extremely salty areas (Utah’s Salt Lake) b. genes are more similar to eukaryotes than eubacteria c. Considered ancient or “archaic” d. Examples: Methanogens: release methane (flatulence in cattle) Thermoacidophiles: live in acidic and extremely hot environments like volcanoes and hot springs Halophiles: salt-loving

Archaebacteria The archaebacteria live in extremely harsh environments, such as: Swamps, salt lakes and hot springs. In fact, the word “archaea” means “archaic or ancient” since many of the known species of archaea live in extreme environments thought to resemble the harsh environments present millions of years ago.

How are Bacteria Structured? Enclosed by a cell wall Contains cytoplasm and hereditary material of the cell Ribsomes are the only organelle found in the cytoplasm

Structure

Bacteria Reproduction a. binary fission (asexual) - one cell undergoes cell division to form two identical daughter cells. b. conjugation (sexual) - a hollow bridge forms between two bacterial cells to transfer genetic info. (increases genetic diversity). c. endospore formation- form spores which forms a protective layer that allows a bacteria cell to survive until conditions are more favorable. (can stay dormant for YEARS!)

Bacteria are Decomposers All living things depend upon a constant supply of: carbon, nitrogen, and other essential elements. These essential elements must be recycled when an organism dies. Some bacteria can digest oil and are helpful in cleaning up oil spills. Bacteria are ___________ that help to ______ these essential chemical elements. decomposers recycle When an organism dies, it is attacked by bacteria and broken down into simpler materials.

Bacteria & Nitrogen Fixation b. Bacteria in soil go through Nitrogen Fixation – the process of changing nitrogen into NH3, a useable form of nitrogen for plants.

Bacteria & You human intestines have large numbers of bacteria and produce vitamins that our body cannot make by itself (symbiotic relationship) used in food like yogurt, cheese, and alcohol.

Diseases Caused by Bacteria How are bacterial infections cured or treated? Use antibiotics to cure bacterial infections What are antibiotics? a chemical that can kill bacteria without harming a person’s cell. What is antibiotic resistance? Bacteria can develop a resistance to antibiotic and will no longer kill This is what happens when you do not take medicine completely What are some examples of diseases caused by bacteria? Anthrax Lyme Disease Leprosy Bacterial Meningitis Strep Throat Tuberculosis

What are Viruses? A virus is a non-cellular particle made up of genetic material and protein that can invade living cells and reproduce.

Viruses are NON-LIVING! With the ability to reproduce, viruses lack nearly every characteristic of life Not composed of cells Do not respond to stimuli Do not use energy for growth and development Need electron microscope to see

How is a virus structured? Contain DNA or RNA (retrovirus) Surrounded by protective protein coat (capsid) Genetic material carries information for multiplication Cannot reproduce without a host cell; hijacks cell’s machinery

Virus Structure

Viral Reproduction : How Do They Do It? Since viruses have no enzymes and no cell parts, they force the host cell to: ___________________. A viral infection begins when: the genetic material (DNA or RNA) of a virus makes its way into a host cell. 3. Once inside, the virus _______ the cell, reprogramming the cell. start making viral parts hijacks

The Two Reproductive Possibilities: Once a virus is inside a host cell, two different processes may occur. Some viruses replicate themselves immediately, killing the host cell. Other viruses replicate themselves in a way that does not destroy the host cell. These two processes are called: a) The lytic cycle b) The lysogenic cycle

Viral Infection – aka “Reproduction” a. Lysogenic Cycle – See Diagram step 1: virus enters the cell step 2: virus incorporates its DNA with host’s DNA indefinitely step 3: virus enters lytic cycle b. Lytic cycle – See Diagram step 1: virus enters cell step 2: cells make copies of virus causing cell to burst (Lyse) and die.

Attachment. Tail fibers are used to attach to receptor sites on the surface of the host cell. A phage that reproduces only by a lytic cycle is called a virulent phage. The Lytic Cycle Entry. Phage DNA is injected. Empty capsid remains outside. Host cell DNA is destroyed. Release. The cell swells, bursts, and releases 100’s of new viruses. Synthesis. The host cell is directed to produce viral genomes and protein capsids. Assembly. The viral DNA or RNA is assembled inside the protein coat.

Certain features determine whether: Phage attaches and injects its DNA. Daughter cell with prophage Many cell divisions may occur, producing a large population of bacteria that are infected with the prophage. Bacterial chromosome Bacteriophage (phage) The host cell bursts, releasing the new viruses. LYTIC LYSOGENIC Bacterial cell divides by binary fission normally. The viral genome is copied and passed to daughter cells. Certain features determine whether: Lytic cycle is induced Lysogenic cycle Is entered Prophage Viral DNA is incorporated into the bacterial chromosome, forming a prophage. New viruses are produced.

How are diseases caused by viruses? Cause disease by either damaging or killing cells CANNOT be treated with antibiotics! Can infect all kinds of cells (plant, bacteria, human) First attaches itself to a healthy cell and then injects its DNA or RNA into cell; then replicates once inside infected cell No Cure, just prevention with vaccine. What are vaccines? Vaccines: a weakened form of the pathogen that when introduced into the body, it will stimulate the production of chemicals that destroy specific viruses or bacteria.

The battle against viral diseases lies in the use of vaccines. Contain a harmless variation of the pathogen. Vaccines: Our immune system launches a response to the harmless form, thereby learning to _________ it the next time that we are ________ to it. When we are exposed to the "real" pathogen, our immune system can respond much faster since it has already learned to recognize the pathogen.

What are some examples of diseases caused by viruses? Rabies Influenza West Nile Virus Viral Meningitis Polio Common Cold Flu AIDS/HIV Chicken Pox Small Pox Yellow Fever Ebola SARS

Measles Rabies Hepatitis H1N1: Swine Flu West Nile Virus H5N1: Avian Flu

Take out a sheet of looseleaf! Write the “Proper Heading” (side whiteboard) Title of assignment: Transmission Simulation Exit Ticket

Transmission Simulation 1. Obtain a plastic cup. 2. “Exchange fluids” with 3 random people in the room by pouring the contents of your cup into theirs, and then pouring half of their cup contents back into yours. Make sure you exchange with others who do not sit near you. 3. After you have exchanged with 3 people, sit down and Mrs. Schenck will put indicator into your cup.

Transmission Simulation Exit Ticket: 1. How many people in the class ended up Infected?___________ Not infected?_________ 2. What percentage of the class was Infected?___________ Not infected?__________ 3. Could you tell by looking at the liquid if it was infected before the indicator was added? Why or why not? 4. How is this a problem in real life? 5. What does this simulation represent? How does it affect YOU?

How are Infectious Diseases Spread? Infectious disease can be spread or be transmitted through the following 4 ways: 1. Direct Contact 2. Indirect Contact through Air 3. Indirect Contact by Objects 4. Vectors

Direct Contact Direct contact with an infected person involves direct body surface to body surface contact and physical transfer of pathogen by touch or the of swapping fluids. You can also infect another person through droplets created when you speak or sneeze. Ex. Mono (“kissing disease”), Common Colds, STD’s

Indirect Contact Indirect contact through air (“airborne illnesses”) Some infectious agents can travel long distances and remain suspended in the air for an extended period of time. You can catch a disease like measles by entering a room after someone with measles has departed. Indirect contact by objects Some organisms can live on objects for a short time. If you touch an object, such as a doorknob, soon after an infected person, you might be exposed to infection. Transmission occurs when you touch your mouth, nose, or eyes before thoroughly washing your hands. Ex. Flu

How do vectors spread disease? A vector is an organism that becomes infected when they feed on infected hosts, such as birds, animals, and humans. The disease is then transmitted when the insect bites a new host. Ex. Water and insects serve as vectors and can transmit diseases such as West Nile & Malaria

Disease Transmission Simulation Exit Ticket: 6. What mode of transmission did the cup exchange activity represent? 7. What mode of transmission did the Glogerm powder represent? 8. How can we prevent ourselves from getting sick or contracting these diseases?

Disease Prevention Humans can prevent the spreading and contraction of infectious diseases by: 1. Wash hands regularly…with soap!!! Statistics show that only 1 in 3 people wash their hands with soap after using the restroom!!! 2. Use hand sanitizer and other disinfectants 3. Stay home when symptoms arise 4. Don’t share personal products 5. Be smart with food preparation 6. Get vaccinated

Disease Transmission Simulation Exit Ticket: 9. After “handwashing” during the cup exchange, what percentage of the class was infected? 10. What have you learned from today’s activities? How can you connect this with your everyday life? Turn in your paper to the inbox when you are done. If time permits, finish the Flu Shot article from yesterday.

Diseases Causes by Protists the protists that cause each of these diseases are caused by parasites Parasite is an organism that takes nourishment or habitat from another organism Most cases do not kill the host Examples Dysentery Malaria *

Picnic Poisoning Activity Goal: To identify the pathogen responsible for an outbreak of a mysterious illness, identify the cause of disease, and propose measures to prevent future outbreak.

Picnic Poisoning Activity On a sheet of looseleaf, with the “Proper Heading”, answer the following questions in complete sentences: What organism caused the disease represented in this activity? What food item was contaminated? Briefly outline the events of the picnic that lead to the spread of this illness. What types of bacteria were “suspects” in this activity? Fill in the “L” column on your KWL chart. Staple questions and chart together and turn into inbox.