1 Latin for “poison” A virus is a particle that can only be seen with an electron microscope.

2 Viruses are not cells and are not made-up of cells. They don’t… Contain a nucleus or cytoplasm Eat Grow Carry on respiration Or perform other biological functions

3 A virus is surrounded by a capsid (protein coat) which determines the shape of the virus. The capsid contains nucleic acids (either DNA or RNA). Tail fibers for attachment to host cell.

4 Viruses are classified by:  type of host cell  presence of DNA or RNA (retroviruses)  shape: Polyhedral Binal Filo

5 VIRAL REPLICATION Viruses replicate in one of two ways: Lytic Lysogenic

6 Virus injects its DNA Virus DNA commands host cell to make new viral parts New viral parts assembled Cell lyses (breaks apart) and new viruses are released Virus attaches to host cell. LYTIC CYCLE

7 LYSOGENIC CYCLE

8 Does not begin immediately Viral DNA (called a prophage) attaches to the host cell’s chromosomes – lies dormant. Environmental stimulus sends viral DNA into lytic cycle. LYSOGENIC CYCLE

9 VIRAL DISEASES DiseaseTransmissionSymptoms AIDS/HIVSexual contact; contaminated blood or needles Immune system failure; fatal Common Cold Inhalation, direct contact Sinus congestion, muscle aches, cough, fever SmallpoxInhalationBlisters, lesions, fever, blindness, scars; often fatal Influenza (Flu) InhalationHeadache, muscle ache, sore throat, cough, fatigue, fever, chills WartsDirect contactLumps on skin or mucus membranes

10 Most viruses have NO cure (Influenza, & HIV), but some viruses like Small- pox have vaccines. Vaccines contain a weakened or killed virus that provides immunity to the disease.

11 BACTERIA Prokaryotic = no nucleus Unicellular = one cell Mostly heterotrophic = cannot make own food

12 Eubacteria and Archaebacteria Two Kingdoms of Bacteria: (Based on differences in structure of DNA, cell wall and cell membrane)

13 “Archae” Means Ancient Live In Extreme Conditions Such As Hot Springs Highly Salty Water Archaebacteria

14 Eubacteria “Eu” (True) Live almost everywhere Fresh and salt water Land In Humans E.coli

15 Identification (based on shapes, cell walls,movement and by the way they obtain energy) Shapes: Bacilli = rods Cocci = round Spirilla = spiral

16 BACILLI (RODS)

17 COCCI (ROUND)

18 SPIRILLI (SPIRAL)

19 Prefixes: Diplo = 2 Strepto = chain Staphylo = clumps A B C

20 More Identification Gram Staining is used to identify bacteria with extra membranes. These bacteria are more resistant to damage. Gram + stain purple Gram – (extra membrane) stain red

21 Even More Identification MOVEMENT: Flagella Glide on slime Wiggle None

22 Reproduction Asexual: Binary fission

23 Endospores: protect genetic material until environment is favorable for reproduction. Sexual: Conjugation

24 Roles Symbiotic relationship – E. coli in the intestines aid in digestion in exchange for food and a warm home.

25 Recycle Chemicals Decomposers Oil-eating bacteria Break-down raw sewage Nitrogen-fixation: change nitrogen to a form that producers can use to make protein.

26 Many fermented foods are produced with the help of bacteria. Cheese Buttermilk Sour cream Vinegar Pickles Sauerkraut Sourdough bread buttermilk

27 Pathogen: Disease-causing Agent Bacteria cause disease in 2 ways: –Damage cells –Release toxins (poisons) Anthrax Acne

28 BACTERIAL DISEASES DiseaseTransmissionDescription of Illness Streptococcus infections Direct contact with saliva or nasal discharge Fever, white patches on tonsils DiphtheriaSneezing or coughing Sore throat, fever, swollen glands AnthraxInhalation of spores Fever, severe difficulty in breathing TuberculosisInhalationFever, difficulty in breathing BotulismContaminated food Blurred vision, difficulty in swallowing, muscle weakness

29 Control Antibiotics: medicines that stop bacterial growth Sterilization: heat or disinfectant Cook food all the way Prevention=vaccines

30 Immune System What is the main function? This system fights infectious diseases.

31 Also, identify “nonself cells” (don’t belong in your body) from “self cells” (belong in your body).

32 GERM THEORY There is a relationship between microorganisms and diseases. Pasteur Lister Koch

33 How are diseases transmitted?

34 What is your first line of defense?  Keep out pathogens  Nonspecific (does not discriminate)

35 Your Second Line of Defense The Inflammatory Response  Reaction to tissue damage  Nonspecific  Redness and swelling

36 THIRD LINE OF DEFENSE  The Immune Response  Specific  Triggered by antigens  Two parts:  Humoral Immunity (B-cells)  Cell-mediated Immunity (T-cells)

37 HUMORAL IMMUNITY Fights pathogens in body fluids. B-cells produce antibodies that mark antigens for destruction.

38 CELL-MEDIATED IMMUNITY  T-cells directly attack harmful cells.  Harmful cells include cancerous, infected or transplanted cells.

39 There are different kinds of T-cells: Killer Helper Suppressor

40 Killer T-cells kill harmful cells.

41 Helper T-cells call in more Killer T-cells and tell the B-cells when to make antibodies.

42 The Suppressor T-cells tell the B-cells to stop making antibodies.

43 ACQUIRED IMMUNITY  Memory T and B cells remember previous antigens.  If the same antigen enters the body again, the memory T and B cells trigger a secondary response. M

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